A wave monitoring method and apparatus

Abstract

The application discloses a wave monitoring method and device, the method comprises the following steps: converting mechanical reciprocating motion caused by sea waves into rotary motion based on a fluid-structure coupling module, and driving a friction power generation module to output a pulse electrical signal; constructing a wave spectrum according to the pulse electrical signal. The device comprises a fluid-structure coupling module, a friction power generation module and a signal receiving module, and the fluid-structure coupling module, the friction power generation module and the signal receiving module are sequentially connected. By using the application, the up-and-down motion energy of waves can be collected to generate different pulse electrical outputs, and then a wave spectrum can be drawn, so that wave monitoring can be realized without an external power supply. The application can be widely applied to the field of vibration sensors such as sea waves and air flows.

Description

Technical Field

[0001] This invention relates to the field of wave sensors, and more particularly to a wave monitoring method and apparatus. Background Technology

[0002] Accurate and effective observation of ocean waves plays a crucial role in numerous marine applications, such as marine disaster prevention and mitigation, marine resource development, marine engineering construction, weather forecasting, marine energy utilization, and research on air-sea interactions. Remote sensing and in-situ instrument observation are two main methods for obtaining wave profiles. However, remote sensing suffers from poor accuracy and the inability to sense waves in real time. In-situ observations using underwater pressure sensors and acoustic profilers also have limitations. For example, acoustic waves are sensitive to environmental noise, and underwater pressure sensors have requirements for shallow water depth. In particular, these sensors always require external power (such as batteries) to monitor waves. Limited power supply capacity severely restricts the time range of marine observations, and the cost of replacing batteries is high. Discarded batteries can also cause serious marine pollution. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a wave monitoring method and apparatus that can collect the up-and-down motion energy of waves and generate different pulse electrical outputs, thereby plotting wave spectra and enabling wave monitoring without the need for an external power source.

[0004] The first technical solution adopted in this invention is: a wave monitoring method, comprising the following steps:

[0005] The fluid-structure interaction module converts the mechanical reciprocating motion caused by ocean waves into rotational motion, and drives the triboelectric power generation module to output pulsed electrical signals.

[0006] Wave spectrum is constructed based on pulse electrical signals.

[0007] Furthermore, the step of converting the mechanical reciprocating motion caused by ocean waves into rotational motion based on the fluid-structure interaction module, and driving the triboelectric power generation module to output pulsed electrical signals, specifically includes:

[0008] The fluid-structure interaction module includes a float, a rack and pinion, a drive gear, a drive shaft, and a one-way overrunning clutch unit.

[0009] The wave motion causes the float and rack to move up and down, which in turn drives the drive gear to rotate.

[0010] The active gear drives the one-way overrunning clutch unit to move, which in turn drives the triboelectric power generation module to move and output pulse electrical signals.

[0011] Furthermore, the step of using the active gear to drive the one-way overrunning clutch unit to move, and then driving the triboelectric power generation module to move and output a pulse electrical signal, specifically includes:

[0012] The one-way overrunning clutch unit includes a first one-way overrunning clutch and a second one-way overrunning clutch.

[0013] The first one-way overrunning clutch and the second one-way overrunning clutch have opposite overrunning directions;

[0014] The first one-way overrunning clutch has a first braking unit on the outer ring of the driven wheel, and the second one-way overrunning clutch has a second braking unit on the outer ring of the driven wheel.

[0015] The triboelectric power generation module includes a first triboelectric generator and a second triboelectric generator;

[0016] The output terminal of the first triboelectric generator is connected to a first diode, and the output terminal of the second triboelectric generator is connected to a second diode;

[0017] When the wave rises, the drive gear rotates clockwise. The first braking unit is not activated, the second braking unit is activated, the first one-way overrunning clutch is engaged, and the second one-way overrunning clutch is overrunning, driving the first triboelectric generator to work. The first diode rectifies the current and outputs a positive pulse current signal.

[0018] When the wave descends, the drive gear rotates counterclockwise, the first braking unit is activated, the second braking unit is not activated, the first one-way overrunning clutch is in the overrunning state, the second one-way overrunning clutch is in the engaged state, driving the second triboelectric generator to work, and outputting a negative pulse current signal through rectification by the second diode.

[0019] Furthermore, both the first and second triboelectric generators employ triboelectric nanogenerators, wherein:

[0020] The triboelectric nanogenerator consists of two parts: a stator and a mover.

[0021] The rotor of the triboelectric nanogenerator uses fluorinated ethylene propylene film as the negative triboelectric material, the stator uses nylon as the positive triboelectric material, and the fan-shaped complementary copper electrode is used as the induction electrode.

[0022] The triboelectric nanogenerator operates using a flexible contact triboelectric power generation method.

[0023] Furthermore, the working process of the triboelectric nanogenerator is as follows:

[0024] In the initial state, the fluorinated ethylene propylene film and the nylon undergo sliding friction, and negative charges accumulate on the surface of the fluorinated ethylene propylene film, while positive charges accumulate on the surface of the nylon.

[0025] In the first stage, the fluorinated ethylene propylene film is fully bonded to the Ea1 electrode in the first complementary electrode.

[0026] As the fluorinated ethylene propylene film gradually slides, the positive charge of the Ea1 electrode in the first complementary electrode is gradually transferred to the Eb1 electrode in the first complementary electrode through the external circuit under the drive of electrostatic induction.

[0027] In the second stage, the fluorinated ethylene propylene film completely overlaps with the Eb1 electrode in the first complementary electrode. All positive charges in the circuit are attracted to the Eb1 electrode in the first complementary electrode, while the Ea1 electrode in the first complementary electrode induces all the negative charges. The direction of movement of the fluorinated ethylene propylene film is in the same direction as the current.

[0028] When the fluorinated ethylene propylene film leaves the Eb1 electrode in the first complementary electrode and begins to slide towards the Ea2 electrode in the second complementary electrode, the positive charge on the Eb1 electrode in the first complementary electrode begins to flow to the Ea2 electrode in the second complementary electrode. Until the third stage, all the positive charge flows into the Ea2 electrode in the second complementary electrode, the charge carried by the Eb1 electrode in the first complementary electrode becomes a negative charge, and the direction of the current flowing through the external circuit is opposite to that in the second stage.

[0029] Cyclic triboelectric charging process.

[0030] Furthermore, the step of constructing the wave spectrum based on the pulse electrical signal specifically includes:

[0031] The pulse electrical signal is denoised to obtain the denoised positive and negative pulse current signals.

[0032] The number of unidirectional pulse currents is counted based on the noise-reduced signal, and the time point corresponding to the peak value is extracted.

[0033] Based on the pre-constructed linear relationship between wave height and pulse current number, positive peak points are converted into wave rise distances, and negative peak points are converted into wave fall distances.

[0034] The wave motion spectrum is plotted based on the time and distance of motion corresponding to the peak point.

[0035] The second technical solution adopted in this invention is: a wave monitoring device, comprising a fluid-structure interaction module, a triboelectric power generation module, and a signal receiving module, wherein the fluid-structure interaction module, the triboelectric power generation module, and the signal receiving module are connected in sequence, wherein:

[0036] The fluid-structure interaction module is used to convert the mechanical reciprocating motion caused by ocean waves into rotational motion and drive the triboelectric power generation module to work.

[0037] The triboelectric power generation module outputs a pulsed electrical signal in response to the braking of the fluid-structure interaction module;

[0038] The signal receiving module is used to receive pulsed electrical signals and construct wave spectra based on the pulsed electrical signals.

[0039] Furthermore, the fluid-structure interaction module includes a float, a rack and pinion, a drive gear, a drive shaft, a first one-way overrunning clutch, and a second one-way overrunning clutch; the triboelectric power generation module includes a first triboelectric nanogenerator and a second triboelectric nanogenerator, wherein:

[0040] A buoy, fixedly connected to a rack and pinion, is used to transmit the motion caused by ocean waves to the rack and pinion.

[0041] A spur rack, matched and connected with a drive gear, is used to convert mechanical reciprocating motion into rotary motion;

[0042] The drive gear is connected to the drive shaft and is used to drive the first one-way overrunning clutch and the second one-way overrunning clutch to work through the drive shaft.

[0043] The first one-way overrunning clutch is connected to the first friction nanogenerator and drives the first friction nanogenerator to work when engaged.

[0044] The second one-way overrunning clutch is connected to the second friction nanogenerator and drives the second friction nanogenerator to work when engaged.

[0045] The first one-way overrunning clutch has a first braking unit on the outer ring of the driven wheel, and the second one-way overrunning clutch has a second braking unit on the outer ring of the driven wheel.

[0046] The output terminal of the first triboelectric nanogenerator is connected to a first diode, and the output terminal of the second triboelectric nanogenerator is connected to a second diode.

[0047] The beneficial effects of the method and apparatus of this invention are as follows: Mechanically, this invention distinguishes the rising and falling processes of waves through an overrunning clutch, thereby driving a triboelectric nanogenerator to operate. The electrical display is then achieved through the rectification effect of diodes, and finally, the wave spectrum is obtained based on the pulse electrical output of the triboelectric nanogenerator, realizing wave sensing without the need for an external power supply. This invention can convert wave energy into electrical energy and monitor the wave motion information carried in the electrical energy, achieving the integration of energy harvesting and motion monitoring, and can be applied to the field of self-powered vibration monitoring. Attached Figure Description

[0048] Figure 1 This is a flowchart of the steps of a wave monitoring method according to the present invention;

[0049] Figure 2 This is a schematic diagram of the structure of a wave monitoring device according to the present invention;

[0050] Figure 3 This is a schematic diagram of the structure of the fluid-structure interaction module in a specific embodiment of the present invention;

[0051] Figure 4 This is a schematic diagram of the structure of a one-way overrunning clutch according to a specific embodiment of the present invention;

[0052] Figure 5 This is an exploded structural diagram of a triboelectric nanogenerator according to a specific embodiment of the present invention;

[0053] Figure 6 This is a schematic diagram of the circuit connection between the triboelectric nanogenerator and the diode in a specific embodiment of the present invention;

[0054] Figure 7 This is a schematic diagram of the device operation in response to a wave according to a specific embodiment of the present invention;

[0055] Figure 8 This is a schematic diagram of the action of a one-way overrunning clutch in response to a wave rising phase according to a specific embodiment of the present invention.

[0056] Figure 9 This is a schematic diagram illustrating the working principle of a first triboelectric nanogenerator responding to a wave rising phase in a specific embodiment of the present invention.

[0057] Figure 10 This is a specific embodiment of the invention that responds to a received pulse current signal during a wave rise phase;

[0058] Figure 11 This is a schematic diagram of the action of a one-way overrunning clutch in response to a wave descent phase according to a specific embodiment of the present invention;

[0059] Figure 12 This is a schematic diagram illustrating the working principle of a second triboelectric nanogenerator responding to a wave descent phase in a specific embodiment of the present invention.

[0060] Figure 13 This is a specific embodiment of the invention that responds to a wave by receiving a pulse current signal;

[0061] Figure 14 This refers to the sensing signal-to-noise ratio under different structural parameters in specific embodiments of the present invention;

[0062] Figure 15 This is the short-circuit current spectrum of a specific embodiment of the present invention after connecting a diode, with a wave height of 60mm and a period of 4000ms;

[0063] Figure 16 This is a schematic diagram illustrating the relationship between pulse current number and wave height under a given period in a specific embodiment of the present invention;

[0064] Figure 17This is a schematic diagram of the performance of a triboelectric nanogenerator in response to 5000 waves (wave height 60mm, period 4000ms) according to a specific embodiment of the present invention.

[0065] Figure 18 This is a schematic diagram of a method for drawing wave spectra according to a specific embodiment of the present invention;

[0066] Figure 19 This is a schematic diagram showing the relationship between the measured and theoretical values ​​of wave height under a given period in a specific embodiment of the present invention;

[0067] Figure 20 This is a schematic diagram showing the relationship between the measured and theoretical values ​​of the wave period under a given wave height, according to a specific embodiment of the present invention.

[0068] Reference numerals: 100, Fluid-structure interaction module; 200, Triboelectric nanogenerator; 101, Float; 102, Spur rack; 103, Driving gear; 104, Drive shaft; 105, One-way overrunning clutch; 1051, Brake wedge; 1052, Driving wheel; 1053, Driven wheel; 1054, Coupling wedge; 201, Mover; 202, Fluorinated ethylene propylene film; 203, Nylon; 204, Ea electrode; 205, Eb electrode; 206, Stator. Detailed Implementation

[0069] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art. Specific Implementation Example 1

[0071] like Figure 1 As shown, the present invention provides a wave monitoring method, which includes the following steps:

[0072] S1. Based on the fluid-structure interaction module, the mechanical reciprocating motion caused by ocean waves is converted into rotational motion, and the triboelectric power generation module is driven to output pulse electrical signals;

[0073] Specifically, refer to Figure 2 and Figure 3 The fluid-structure interaction module includes a hollow foam float, a rack and pinion, a drive gear, a drive shaft, a first one-way overrunning clutch and a second one-way overrunning clutch, and the triboelectric power generation module includes a first triboelectric nanogenerator (TENG) and a second triboelectric nanogenerator.

[0074] Both the first one-way overrunning clutch and the second one-way overrunning clutch are equipped with ratchet teeth and ratchet brake wedges on the outer ring of the driven wheel for braking.

[0075] Both the first and second triboelectric nanogenerators have diodes at their output terminals.

[0076] Without the diode connection, it is impossible to distinguish the rising or falling process of the wave from the triboelectric signal output by the TENG. To solve this problem, we connected two diodes in the sensor.

[0077] Reference Figure 4 and Figure 5 The working process is described by combining the structures of a one-way overrunning clutch and a triboelectric nanogenerator:

[0078] S1.1 When the wave rises, the hollow foam float moves upward and drives the drive gear to rotate clockwise via the rack. At this time, the inner ratchet of the driven wheel of the first one-way overrunning clutch is tightly engaged with the coupling wedge, while the outer ratchet of the driven wheel slides over the brake wedge of the first braking unit under the action of the spring. The first braking unit is not activated. Therefore, the driven wheel moves with the drive gear, thereby driving the first one-way overrunning clutch to work, and then driving the first friction nanogenerator to generate frictional power. After rectification by the diode, a positive pulse current signal is output. However, at this time, the second one-way overrunning clutch is in an overrunning state. Its coupling wedge slides over the inner ratchet of the driven wheel under the action of the spring, and at the same time, the outer ratchet of the driven wheel engages with the ratchet of the brake wedge. The second braking unit is activated. Therefore, the driven wheel does not move with the drive gear and cannot drive the second friction nanogenerator to generate frictional power.

[0079] S1.2 When the wave descends, the situation is exactly the opposite. At this time, the hollow foam float moves downward and drives the drive gear to rotate counterclockwise through the rack. Since the overrunning directions of the two overrunning clutches are opposite, the first one-way overrunning clutch is in the overrunning state, while the second one-way overrunning clutch is in the engaged state. This drives the second triboelectric nanogenerator to generate triboelectric power, which is then rectified by the diode and output as a negative pulse current signal.

[0080] Therefore, in this project, the movement of the drive gear (i.e., the engagement state of the two one-way overrunning clutches) corresponds to the rising and falling of the wave, respectively. Different pulse electrical outputs can be generated using diodes, and the wave spectrum can be obtained from these electrical signals. The working process and principle of a wave can be found in [reference needed]. Figures 7-13 The same markings on the diagram represent the corresponding stages.

[0081] Specifically, this invention converts the vertical motion of waves into continuous rotational motion, which has a significant advantage in improving energy conversion efficiency. Through a one-way overrunning clutch with a braking unit, the energy of the vertical motion of waves can be effectively collected and converted into rotational motion in different directions of a triboelectric nanogenerator, thereby generating different pulse electrical outputs.

[0082] The triboelectric nanogenerator consists of a stator and a mover. Both movers of the two triboelectric nanogenerators are coupled to the driven wheel of a one-way overrunning clutch in a fluid-structure interaction module, allowing the rising and falling waves to correspond to the rotational power output of different triboelectric nanogenerators. For the stator, multi-gate induction electrodes are coated onto a circular epoxy fiberglass substrate using printed circuit board (PCB) technology, and then a layer of nylon is fully covered on top of the electrodes as the positive triboelectric material. The induction electrodes consist of radially arrayed sectors, with each pair of adjacent sectors separated by fine trenches, forming two complementary electrodes, namely electrode Ea and electrode Eb. For the mover, a layer of fluorinated ethylene propylene film (FEP) is selected as the negative triboelectric material. This structure eliminates the need for electrode deposition or connecting wires on the rotating mover, greatly improving the flexibility of device operation. To reduce wear of the friction material during rotation and to reduce friction that hinders wave drive, TENG employs a flexible contact triboelectric generation method, where one end of the FEP is adhered to the mover, while the other end is free, utilizing the elasticity of the FEP to effectively contact the nylon. The shape of the overlapping region between FEP and nylon is the same as that of the sector electrode unit. Each time the FEP film sweeps across a sector electrode, the TENG generates a pulse voltage output. The working process of the triboelectric nanogenerator is as follows:

[0083] The charge transfer in the flexible contact TENG consists of three stages. Initially, the FEP film undergoes sliding friction with the nylon. Due to the stronger electronegativity of FEP compared to nylon, negative charges accumulate on the FEP surface, while positive charges accumulate on the nylon surface. When the frictional charge between FEP and nylon reaches saturation, equal amounts of positive and negative charges accumulate on their surfaces. At this point, if the FEP film is fully bonded to Ea1 in the first complementary electrode, this is defined as the first stage (…). Figure 9 -i). As the FEP film gradually slides, the positive charge on the first complementary electrode Ea1 is gradually transferred to the first complementary electrode Eb1 through the external circuit under the drive of electrostatic induction. When the FEP film and the first complementary electrode Eb1 are completely aligned, all the positive charges in the circuit are attracted to the first complementary electrode Eb1, and the first complementary electrode Ea1 is induced with all the negative charges. During this process, the direction of movement of the FEP film is the same as that of the current, which is the second stage ( Figure 9-ii). When the FEP leaves the first complementary electrode Eb1 and begins to slide towards the second complementary electrode Ea2, the positive charge on the first complementary electrode Eb1 begins to flow to the second complementary electrode Ea2. This continues until the third stage, when all the positive charge flows into the second complementary electrode Ea2, and the charge carried by the first complementary electrode Eb1 becomes a negative charge. Figure 9 -iii), in this stage, the direction of the current flowing through the external circuit is opposite to that in the second stage. The above two stages constitute a complete triboelectric charging process. When the FEP continues to slide and comes into contact with the second complementary electrode Eb2, the triboelectric charging process will repeat. Figure 9 -iv).

[0084] The rectifier circuit uses the unidirectional conductivity of the diode to convert the positive and negative currents output by Ea and Eb into unidirectional pulsed DC signals. Figure 6 -i represents the circuit diagram showing the connection between the triboelectric nanogenerator and the diode. For example... Figure 6 As shown in -ii, during the positive half-cycle of the AC power supply, the diode conducts, allowing the load to receive forward current. However, during the negative half-cycle, the diode is in reverse cutoff, bearing the negative half-cycle voltage of the power supply, while the voltage on the external load is almost zero. Figure 10 and 13 The diagram illustrates the corresponding current signals output by the TENG connected to the diode during wave rise and fall. It can be seen that after diode rectification, the positive and negative triboelectric signals correspond to the rise and fall of the waves, respectively, allowing for accurate differentiation of the wave's undulation state.

[0085] S2. Construct wave spectrum based on pulse electrical signal.

[0086] After collecting triboelectric pulse signals using an electrometer, we can invert these signals into wave information based on the mapping relationship between triboelectric signals and wave motion (the number of pulse currents represents the wave height, and the duration of two adjacent sets of positive and negative signals represents the wave period; details will be introduced in later chapters). Finally, we can use a LabVIEW program to achieve real-time visualization of the wave information.

[0087] S2.1. The output signal of TENG is denoised to obtain the denoised pulse current signal, such as... Figure 18 -i is shown;

[0088] S2.2 Count the number of unidirectional pulse currents from these signals and extract the time points corresponding to the peak values;

[0089] S2.3, according to Figure 16 The linear relationship between wave height and pulse current number converts positive peak points into the rising distance of the wave and negative peak points into the falling distance of the wave.

[0090] In addition, by using different settings, positive peak points can be represented as the wave's downward distance, and negative peak points can be represented as the wave's upward distance. The basic principle remains the same, and the specific settings are not listed here.

[0091] The wave motion spectrum (y-axis represents wave motion distance, x-axis represents time) is composed of scattered points. The vertical motion distance of each scattered point (i.e., the height of the y-axis) can be calculated based on the number of pulse currents. Specifically, if there are 6 positive and 6 negative pulse currents, all positive peak points in one cycle are numbered sequentially starting from 1, and negative peak points are numbered in reverse order, such as 1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1, 0. The resulting numbering corresponds one-to-one with the peak points. Then, the motion distance of all peak points is calculated based on the linear relationship between wave height and pulse current number.

[0092] S2.4. The wave motion spectrum can be drawn based on the time point and movement distance corresponding to the peak, such as... Figure 18 As shown in -ii, in two adjacent sets of positive and negative signals, the time interval between the first positive peak point and the last negative peak point is the wave period.

[0093] The performance of this method is characterized as follows:

[0094] Wave height and period are two important parameters for evaluating ocean performance. To assess the performance of our self-powered sensor, we built an indoor simulated wave self-powered monitoring platform, using a high-precision linear motor (LinMot PS01-37×120-C) to simulate different wave heights and periods. This motor, acting as an external driver, can provide precise and varied motion modes by setting parameters such as vertical movement distance, acceleration, and maximum speed through the control interface. We approximate the rise or fall distance of the buoy as the wave height. Therefore, the electrical output performance of the self-powered sensor depends on the buoy's motion profile. Through self-powering, we can acquire the buoy's motion information and calculate the wave height and period from it.

[0095] Based on S2 above, the higher the signal quality, the easier it is to extract the true signal from the noise signal. The signal-to-noise ratio (SNR) is one of the important indicators characterizing signal quality. Since the SNR reflects the relationship between the true signal and noise, we need to improve the sensor's SNR in order to effectively identify wave information.

[0096] A high signal-to-noise ratio (SNR) is essential to ensure that the sensing signal is unaffected by noise. In this work, the number and thickness (δ) of the FEP film, and the distance (L) between the mover and stator, determine the output of triboelectric charge, thus affecting the SNR. To optimize the sensor's performance in wave monitoring, we systematically investigated the influence of structural parameters such as the number and thickness (δ) of the FEP film and the distance (L) between the mover and stator on the SNR. Figure 14It can be seen that when the distance is 5 mm, the signal-to-noise ratio (SNR) hardly changes with the thickness (δ) or number of FEP films. However, when the distance increases to 10 mm, the SNR drops rapidly by 48.6% (from 15.79 dB to 8.12 dB). This is because the distance (L) between the mover and stator determines the effective friction area between the FEP and nylon, thus affecting the sensor's electrical output and SNR. This indicates that, compared to the thickness (δ) and the number of FEP films, the distance (L) is the most important factor affecting the sensor's output signal. Although the number of FEP films also affects the SNR, increasing the number of FEP films also increases the frictional force, thus requiring a larger wave force to drive the sensor. Figure 14 As shown in section -ii, compared to 2, 6, and 8 FEP films, the 4-film FEP film exhibits the highest signal-to-noise ratio. Therefore, to ensure better sensor performance, we used 4 FEP films with a thickness of 0.2 mm and set the distance between the mover and stator to 5 mm. Since smaller-area sector-shaped complementary electrode units correspond to higher electrical output frequencies and sensing resolutions, we selected 48 sector-shaped complementary electrodes as the triboelectric generation module for orthogonal experiments.

[0097] We evaluated the sensor's electrical output performance without connecting diodes. As wave height increased, the frequency of the electrical output increased, and the number of pulse currents also increased accordingly, indicating a mapping relationship between wave height and pulse current count. Furthermore, when the period was constant, the duration corresponding to wave rise or fall was consistent regardless of wave height variation; therefore, wave height and period monitoring were independent. However, without diode connections, it was impossible to distinguish the rise or fall of the wave from the triboelectric signal output by the TENG. To address this issue, we connected two diodes in the sensor. Figure 15 The short-circuit current spectrum of the sensor connected to the diode is shown at a wave height of 60 mm and a period of 4000 ms. Through rectification by the diode, the sensor generates periodic pulse signals, where positive and negative pulse signals correspond to the rising and falling of the wave, respectively, thus distinguishing the up-and-down movement of the wave. N in the figure... + and N - t represents the number of positive and negative pulse currents, respectively. o and t f These represent the times corresponding to the first positive pulse signal and the last negative pulse signal in the simulated wave period, respectively. It can be observed that at the same wave height, the number of positive and negative pulse currents is almost equal, but t... o and t f The time interval between them increases with the increase of the wave period. For example, when the period is 8000 ms, t o and t fThe time between them is approximately twice that at 4000ms, which indicates that t o and t f The time interval between these events can reflect wave period information. Furthermore, as wave height increases, the number of pulse currents increases linearly, but the current amplitude does not change significantly. Therefore, we can calculate the wave period by extracting the time corresponding to the first positive peak signal and the last negative peak signal in the simulated wave period, and determine the wave height by calculating the number of pulse currents.

[0098] This study first explored the relationship between simulated wave height and the number of pulse currents. To ensure the validity of the statistical results, 20 repeated measurements of the pulse current were performed at a given simulated wave height. The results show that the number of pulse currents and wave height exhibit a good linear relationship, with a correlation coefficient reaching 0.9923. Figure 16 As shown. Furthermore, from Figure 16 It can also be seen that as the wave height increases, the mean value of the pulse current count deviates slightly from the fitted curve, and the error becomes larger. This is due to the inertial force of the mover. After the float rises to the wave crest, the inertial force causes the TENG's rotation not to stop immediately, but to continue for a short period of time, resulting in errors in the pulse current count. When the wave period is given, an increase in wave height means an increase in the acceleration of wave motion, and therefore an increase in inertial force, leading to even greater errors. To verify the stability of the TENG, it was placed under simulated waves with a wave height of 80 mm and a period of 4000 ms and operated continuously for 5000 cycles, referring to... Figure 17 The results show that the electrical performance of the TENG was not affected after responding to 5000 waves. Therefore, the good linear relationship between the pulse current number and wave height, as well as the stability of the TENG in the simulated wave environment, provide a theoretical basis and experimental evidence for its application in wave sensing.

[0099] The wave height information extracted using this method is as follows: Figure 19 As shown in the figure. The results indicate that, within a given wave period of 4000 ms, there is an excellent linear relationship between the measured and theoretical values ​​of various wave heights, with a linearity coefficient exceeding 99%, demonstrating the effectiveness of this method for wave height monitoring. Figure 20 As shown, at a given wave height, the linearity between the measured wave period and the theoretical value is as high as 0.9989, indicating that the method has high accuracy in wave period monitoring.

[0100] Due to the limitation of the linear motor's travel distance, the upper limit of the simulated wave height in the laboratory is within 200mm. Since the vertical movement distance of the wave is linearly related to the number of pulses rather than the current amplitude, the upper limit of wave height measurement is not limited by the friction area. This invention can achieve wide-range wave height monitoring. Specific Implementation Example 2

[0102] Reference Figures 2-6 A wave monitoring device includes a fluid-structure interaction module, a triboelectric power generation module, and a signal receiving module, wherein the fluid-structure interaction module, the triboelectric power generation module, and the signal receiving module are connected in sequence, wherein:

[0103] The fluid-structure interaction module is used to convert the mechanical reciprocating motion caused by ocean waves into rotational motion and drive the triboelectric power generation module to work.

[0104] The triboelectric power generation module outputs a pulsed electrical signal in response to the braking of the fluid-structure interaction module;

[0105] The signal receiving module is used to receive pulsed electrical signals and construct wave spectra based on the pulsed electrical signals.

[0106] In this embodiment, the fluid-structure interaction module includes a hollow foam float, a rack, a drive gear, a drive shaft, a pair of one-way overrunning clutches, and a braking unit. To prevent the sensor from being contaminated by seawater, all sensor components except the float, rack, and drive gear are encapsulated in two acrylic boxes.

[0107] The drive gear can convert the reciprocating linear motion of waves into continuous rotational motion, without being affected by the vertical movement distance of the waves. In this way, the observation range of wave height is no longer limited by the size of the device.

[0108] The outer ring of the driven wheel of the one-way overrunning clutch is equipped with ratchet teeth and ratchet brake wedges to brake the overrunning clutch and to keep the pitch of the ratchet teeth consistent with that of the driving gear.

[0109] When the driving wheel of the first one-way overrunning clutch rotates clockwise, the coupling wedge is tightly engaged with the driven wheel under the push of the spring. At this time, the first one-way overrunning clutch is in the working engaged state, and the first braking unit is not activated. In this way, the driving wheel transmits torque to the driven wheel, driving the rotating rotor of the first friction nanogenerator (coupled to the driven wheel) to rotate clockwise. When the driving wheel rotates counterclockwise, the coupling wedge slides down the inner ratchet of the driven wheel under the action of the spring. The first one-way overrunning clutch is in the overrunning state, and the first braking unit is activated. At this time, the driving wheel cannot transmit torque and cannot drive the rotor of the first friction nanogenerator to rotate.

[0110] However, the direction of the vertical motion of the waves cannot be identified from the AC signal output by the triboelectric nanogenerator because the gears rotate regardless of whether the waves are rising or falling. In fact, the rotation directions caused by rising and falling waves are different, and thus the rise and fall of waves can be distinguished based on the rotation direction. To mechanically distinguish the rotation direction, we designed an intelligent mechanical structure—a one-way overrunning clutch with a built-in braking unit.

[0111] A one-way overrunning clutch has two modes of motion: overrunning (i.e., the driven wheel does not rotate with the driving wheel) and engagement (i.e., the driven wheel rotates synchronously under the drive of the driving wheel). Torque can be transmitted when force is transmitted along the engagement direction, and not when it is not. The one-way overrunning clutch can select whether to accept torque transmission from the driving wheel and generate drive based on the set overrunning direction. This mechanism can convert the up-and-down motion of waves into rotational motion in a single direction.

[0112] The two one-way overrunning clutches have opposite overrunning directions, so that the rising or falling motion of the wave can be accurately transmitted to one of the one-way overrunning clutches, putting it into engagement.

[0113] When the sensor is driven by a float, friction between the structures generates resistance, thus requiring the float to have a greater draft to produce greater buoyancy to drive the sensor. To accurately monitor waves, the resistance acting on the float needs to be minimized, thereby reducing the required draft. To achieve this, we construct a fluid-structure interaction device using a hollow straight rack and float made of acrylonitrile butadiene styrene (ABS).

[0114] In this embodiment, the triboelectric power generation module includes two triboelectric nanogenerators (TENGs), each consisting of a stator and a mover. The movers of both TENGs are coupled to the driven wheel of an overrunning clutch in a fluid-structure interaction module, allowing the rising and falling of waves to correspond to the rotational power generation output of different TENGs. For the stator, multi-gate induction electrodes are coated onto a circular epoxy fiberglass substrate using printed circuit board (PCB) technology, and then a layer of nylon is fully covered on top of the electrodes as the positive triboelectric material. The induction electrodes consist of radially arrayed sectors, with each pair of adjacent sectors separated by fine trenches, forming two complementary electrodes, namely electrode Ea and electrode Eb. For the mover, a layer of fluorinated ethylene propylene (FEP) film is selected as the negative triboelectric material. This structure eliminates the need for electrode deposition or connecting wires on the rotating mover, significantly improving the operational flexibility of the device. To reduce wear of the friction material during rotation and to reduce friction that hinders wave drive, the TENG employs a flexible contact triboelectric power generation method, where one end of the FEP adheres to the mover, while the other end is free, utilizing the elasticity of the FEP to effectively contact the nylon. The shape of the overlapping area between FEP and nylon is the same as that of the sector electrode unit. Each time the FEP film sweeps across a sector electrode, TENG generates a pulse voltage output.

[0115] In this embodiment, all stators and movers of the triboelectric nanogenerator have a diameter of 20 cm. The stator substrate is a circular epoxy fiberglass board (1.6 mm thick). A copper electrode layer (35 μm thick) with a central hole of 3.6 cm is coated on the substrate using printed circuit board (PCB) technology. The copper electrode has 48 complementary fan-shaped regions, each with a central angle of approximately 7.5 degrees. Then, a 50 μm thick nylon film is attached above the electrode layer as the positive triboelectric material. A 5 mm through hole is drilled around the center of the stator for bolt connection. For the mover, a 3 mm thick acrylic plate is laser-processed into a 20 cm diameter circle, and eight evenly distributed 70 mm × 1.2 mm holes are embedded. Eight fan-shaped 200 μm thick FEP films are inserted into these holes and fixed with tape as the negative triboelectric material.

[0116] In this embodiment, the one-way overrunning clutch mainly consists of a driving wheel, a driven wheel, a coupling wedge, and a braking wedge. All parts are 3D printed from acrylonitrile butadiene styrene (ABS). The driving wheel is spindle-shaped, 26mm wide and 50mm long, with a 6mm through hole drilled in the center for connection to the drive shaft. The driven wheel has inner and outer diameters of 54mm and 80mm, respectively, and is designed as ratchet wheels in opposite directions. The number of teeth on the ratchet wheels is 36 and 40, respectively. The driven wheel is bolted to the moving part on the back. The driving wheel engages or disengages with the inner ring ratchet teeth of the driven wheel via a spring-loaded coupling wedge. Similarly, on the outer ring of the driven wheel, the braking wedge brakes or releases the outer ring through the action of a spring.

[0117] The content of the above method embodiments is applicable to the device embodiments. The specific functions implemented in the system embodiments are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0118] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A wave monitoring method, characterized in that, Includes the following steps: The fluid-structure interaction module converts the mechanical reciprocating motion caused by ocean waves into rotational motion, and drives the triboelectric power generation module to output pulsed electrical signals. Constructing wave spectra based on pulsed electrical signals; The step of converting the mechanical reciprocating motion caused by ocean waves into rotational motion based on the fluid-structure interaction module, and driving the triboelectric power generation module to output pulsed electrical signals, specifically includes: The fluid-structure interaction module includes a float, a rack and pinion, a drive gear, a drive shaft, and a one-way overrunning clutch unit. The wave motion causes the float and rack to move up and down, which in turn drives the drive gear to rotate. The active gear drives the one-way overrunning clutch unit to move, which in turn drives the triboelectric power generation module to move and output pulse electrical signals. The step of using a drive gear to drive a one-way overrunning clutch unit to move, and then driving a triboelectric power generation module to move and output a pulse electrical signal, specifically includes: The one-way overrunning clutch unit includes a first one-way overrunning clutch and a second one-way overrunning clutch. The first one-way overrunning clutch and the second one-way overrunning clutch have opposite overrunning directions; The first one-way overrunning clutch has a first braking unit on the outer ring of the driven wheel, and the second one-way overrunning clutch has a second braking unit on the outer ring of the driven wheel. The triboelectric power generation module includes a first triboelectric generator and a second triboelectric generator; The output terminal of the first triboelectric generator is connected to a first diode, and the output terminal of the second triboelectric generator is connected to a second diode; When the wave rises, the drive gear rotates clockwise. The first braking unit is not activated, the second braking unit is activated, the first one-way overrunning clutch is engaged, and the second one-way overrunning clutch is overrunning, driving the first triboelectric generator to work. The first diode rectifies the current and outputs a positive pulse current signal. When the wave descends, the drive gear rotates counterclockwise, the first braking unit is activated, the second braking unit is not activated, the first one-way overrunning clutch is in the overrunning state, the second one-way overrunning clutch is in the engaged state, driving the second triboelectric generator to work, and outputting a negative pulse current signal through rectification by the second diode. Both the first braking unit and the second braking unit are ratchet and ratchet brake wedge blocks.

2. The wave monitoring method according to claim 1, characterized in that, Both the first and second triboelectric generators employ triboelectric nanogenerators, wherein: The triboelectric nanogenerator consists of two parts: a stator and a mover. The rotor of the triboelectric nanogenerator uses fluorinated ethylene propylene film as the negative triboelectric material, the stator uses nylon as the positive triboelectric material, and the fan-shaped complementary copper electrode is used as the induction electrode. The triboelectric nanogenerator operates using a flexible contact triboelectric power generation method.

3. The wave monitoring method according to claim 2, characterized in that, The working process of the triboelectric nanogenerator is as follows: In the initial state, the fluorinated ethylene propylene film and the nylon undergo sliding friction, and negative charges accumulate on the surface of the fluorinated ethylene propylene film, while positive charges accumulate on the surface of the nylon. In the first stage, the fluorinated ethylene propylene film is fully bonded to the Ea1 electrode in the first complementary electrode. As the fluorinated ethylene propylene film gradually slides, the positive charge of the Ea1 electrode in the first complementary electrode is gradually transferred to the Eb1 electrode in the first complementary electrode through the external circuit under the drive of electrostatic induction. In the second stage, the fluorinated ethylene propylene film completely overlaps with the Eb1 electrode in the first complementary electrode. All positive charges in the circuit are attracted to the Eb1 electrode in the first complementary electrode, while the Ea1 electrode in the first complementary electrode induces all the negative charges. The direction of movement of the fluorinated ethylene propylene film is in the same direction as the current. When the fluorinated ethylene propylene film leaves the Eb1 electrode in the first complementary electrode and begins to slide towards the Ea2 electrode in the second complementary electrode, the positive charge on the Eb1 electrode in the first complementary electrode begins to flow to the Ea2 electrode in the second complementary electrode. Until the third stage, all the positive charge flows into the Ea2 electrode in the second complementary electrode, the charge carried by the Eb1 electrode in the first complementary electrode becomes a negative charge, and the direction of the current flowing through the external circuit is opposite to that in the second stage. Cyclic triboelectric charging process.

4. The wave monitoring method according to claim 3, characterized in that, The step of constructing the wave spectrum based on the pulse electrical signal specifically includes: The pulse electrical signal is denoised to obtain the denoised signal. The number of unidirectional pulse currents is counted based on the noise-reduced signal, and the time point corresponding to the peak value is extracted. Based on the pre-constructed linear relationship between wave height and pulse current number, positive peak points are converted into wave rise distances and negative peak points are converted into wave fall distances. The wave motion spectrum is plotted based on the time point and movement distance corresponding to the peak.

5. A wave monitoring device, characterized in that, The system is used to execute the wave monitoring method as described in claim 1, comprising a fluid-structure interaction module, a triboelectric generation module, and a signal receiving module, wherein the fluid-structure interaction module, the triboelectric generation module, and the signal receiving module are connected in sequence, wherein: The fluid-structure interaction module is used to convert the mechanical reciprocating motion caused by ocean waves into rotational motion and drive the triboelectric power generation module to work. The triboelectric power generation module outputs a pulsed electrical signal in response to the braking of the fluid-structure interaction module; The signal receiving module is used to receive pulsed electrical signals and construct wave spectra based on the pulsed electrical signals.

6. The wave monitoring device according to claim 5, characterized in that, The fluid-structure interaction module includes a float, a rack and pinion, a drive gear, a drive shaft, a first one-way overrunning clutch, and a second one-way overrunning clutch. The triboelectric power generation module includes a first triboelectric nanogenerator and a second triboelectric nanogenerator, wherein: A buoy, fixedly connected to a rack and pinion, is used to transmit the motion caused by ocean waves to the rack and pinion. A spur rack, matched and connected with a drive gear, is used to convert mechanical reciprocating motion into rotary motion; The drive gear is connected to the drive shaft and is used to drive the first one-way overrunning clutch and the second one-way overrunning clutch to work through the drive shaft. The first one-way overrunning clutch is connected to the first friction nanogenerator and drives the first friction nanogenerator to work when engaged. The second one-way overrunning clutch is connected to the second friction nanogenerator and drives the second friction nanogenerator to work when engaged. The first one-way overrunning clutch has a first braking unit on the outer ring of the driven wheel, and the second one-way overrunning clutch has a second braking unit on the outer ring of the driven wheel. The output terminal of the first triboelectric nanogenerator is connected to a first diode, and the output terminal of the second triboelectric nanogenerator is connected to a second diode.

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