Bridge self-powered displacement-acceleration sensing system based on hybrid energy harvesting

Abstract

The invention discloses a self-powered displacement-acceleration sensing system for a bridge based on hybrid energy collection. The hybrid energy collection device converts wind energy into electrical energy and then passes through a power management circuit to convert it into a DC voltage to power the remaining units. The hybrid energy collector includes a ball with a FEP surface, a coaxially sleeved and rotatable cone cylinder 1, cone cylinder 2 or spindle cylinder 1, spindle cylinder 2, and upper and lower blades with opposite torsional directions. The outer wall of the upper cylinder, the inner wall of the lower cylinder, and the upper and lower blades are all provided with multiple tracks to accommodate the ball, and the tracks of the upper and lower cylinders are connected end to end. The inner wall of the upper cylinder is attached with grid-shaped copper electrodes at intervals in the circumferential direction, and polyester fiber wool is arranged in the gap. The coil embedded in the bottom surface of the upper cylinder cooperates with the permanent magnet embedded in the bottom surface of the lower cylinder. The outer wall of the lower cylinder is evenly and staggeredly attached with multiple nylon films and PTFE films in the circumferential direction. The invention realizes the self-power supply of the sensing system and ensures the continuous and stable operation of the self-powered displacement-acceleration sensing system for the bridge.

Description

Technical Field

[0001] The invention relates to the fields of wind power generation and environmental energy development, and in particular to a bridge self-powered displacement-acceleration sensing system based on hybrid energy collection. Background Art

[0002] As a vital connection point in the transportation network, bridges carry the important task of connecting different regions and facilitating the flow of people and goods. Their durability and safety directly affect the safety of people's lives and property, as well as the smooth development of economic and social activities. However, over time, bridges may suffer structural damage and fatigue due to factors such as continuous use, environmental erosion, and overload, which increases the risk of failure. Therefore, continuous monitoring and health assessment of bridges is particularly critical.

[0003] In the bridge health monitoring system, displacement sensors and accelerometers play a vital role. These sensors can monitor the displacement and acceleration of the bridge structure in real time, including parameters such as vibration and deformation. By recording and analyzing this data, engineers and technicians can promptly detect changes in the bridge structure and identify potential problems. The use of displacement sensors and accelerometers can help determine the load-bearing status of the bridge, monitor potential signs of structural damage, and warn of possible safety risks in advance. Therefore, their importance in the bridge health monitoring system is self-evident. They provide key real-time data support to ensure the safety of the bridge, help to take timely and effective maintenance and repair measures, and ensure the long-term stable operation of the bridge, thereby protecting people's lives and property. However, the currently widely used displacement and acceleration sensing technologies usually rely on battery power, but the inconvenience of battery maintenance and replacement installed on the bridge brings many challenges to the monitoring system. Sometimes, this even causes the monitoring system to fail temporarily during maintenance, affecting the monitoring and safety of the bridge. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention proposes a bridge self-powered displacement-acceleration sensing system based on hybrid energy harvesting.

[0005] The specific technical solutions are as follows:

[0006] A self-powered displacement-acceleration sensing system for a bridge based on hybrid energy collection, comprising: a hybrid energy collection device, a power management circuit, a sensing unit, and a micro-control unit; the hybrid energy collection device is used to convert wind energy into electrical energy, the power management circuit is used to convert the alternating current generated by the hybrid energy collection device into a direct current voltage to power the sensing unit and the micro-control unit; the sensing unit comprises a displacement sensor and an acceleration sensor, and the micro-control unit is used to transmit data of the sensing unit; the hybrid energy collector comprises: an upper cylinder, a lower cylinder, a base, and a ball; the upper cylinder and the lower cylinder are coaxially sleeved on the base and can rotate around a central axis;

[0007] The upper cylinder comprises: a conical cylinder 1, a track 1, a fan blade 1, a track 2, a coil, a grid-shaped copper electrode, and polyester fiber wool; the conical cylinder 1 is a hollow cone with an opening at the bottom, the fan blades are coaxially fixed to the top of the cone, and the fan blade 1 comprises a plurality of blades twisted in the same direction; a plurality of tracks 1 surrounding the circumference end to end are arranged on the outer wall of the conical cylinder 1, and a plurality of tracks 2 are arranged on each blade of the fan blade 1; a fan-shaped grid-shaped copper electrode is attached to the inner wall of the conical cylinder 1, and a plurality of gaps 1 are evenly arranged in the circumference of the grid-shaped copper electrode, and each gap 1 is arranged in each gap, and polyester fiber wool is arranged in the gap 1; a plurality of coil slots are evenly arranged in the circumference of the inner wall of the conical cylinder 1, and a coil is installed in each coil slot, and the coils are divided into two groups according to the position intervals, and the coils in the group are connected in series when connected, and the two coil windings are connected in parallel after passing through the rectifier bridge;

[0008] The lower cylinder comprises: a second cone cylinder, a third track, a second blade, a fourth track, a permanent magnet, a nylon membrane, and a PTFE membrane; the second cone cylinder is a hollow cone with an opening at the bottom, and a cone cylinder is coaxially sleeved on the outer periphery of the second cone cylinder, and the size of the second cone cylinder is adapted to the hollow part of the first cone cylinder; the bottom center of the second cone cylinder is coaxially fixedly connected to the second blade, and the second blade comprises a plurality of blades twisted in the same direction, and the twisting direction of the blades is opposite to that of the first blade; a plurality of circumferential head and tail rings are arranged on the inner wall of the second cone cylinder The outer wall of the conical cylinder 2 is uniformly attached with a plurality of fan-shaped nylon membranes and PTFE membranes in a circumferential direction, the number of nylon membranes and PTFE membranes is the same, the size is the same, the two membranes are staggered and attached, and a gap 2 is left between two adjacent membranes; a plurality of permanent magnet slots are uniformly opened in a circumferential direction on the inner wall of the conical cylinder 2, a permanent magnet is installed in each permanent magnet slot, the permanent magnets are staggered in NS arrangement according to the position, and the ratio of the number of permanent magnets to the number of coils is 1:1;

[0009] Grid-shaped copper electrodes are laid inside the track one, track two, track three and track four. The surface material of the ball is FEP, which is installed in the track one, track two, track three and track four respectively and can slide and roll therein.

[0010] A self-powered displacement-acceleration sensing system for a bridge based on hybrid energy collection, comprising: a hybrid energy collection device, a power management circuit, a sensing unit, and a micro-control unit; the hybrid energy collection device is used to convert wind energy into electrical energy, the power management circuit is used to convert the alternating current generated by the hybrid energy collection device into a direct current voltage to power the sensing unit and the micro-control unit; the sensing unit comprises a displacement sensor and an acceleration sensor, and the micro-control unit is used to transmit data of the sensing unit; the hybrid energy collector comprises: an upper cylinder, a lower cylinder, a base, and a ball; the upper cylinder and the lower cylinder are coaxially sleeved on the base and can rotate around a central axis;

[0011] The upper cylinder comprises: a spindle cylinder 1, a track 1, a fan blade 1, a track 2, a coil, a grid-shaped copper electrode, and polyester fiber wool; the spindle cylinder 1 is a hollow spindle; the fan blades are coaxially fixedly connected to the top thereof, and the fan blade 1 comprises a plurality of blades twisted in the same direction; a plurality of tracks 1 which are circumferentially encircled end to end are provided on the outer wall of the spindle cylinder 1, and a plurality of tracks 2 are provided on each blade of the fan blade 1; a fan-shaped grid-shaped copper electrode is attached to the inner wall of the spindle cylinder 1, and a plurality of gaps 1 are uniformly provided on the grid-shaped copper electrode in the circumferential direction, and each gap 1 is provided between each gap 1, and polyester fiber wool is arranged in the gap 1; a plurality of coil slots are uniformly provided on the inner wall of the spindle cylinder 1 in the circumferential direction, and a coil is installed in each coil slot, and the coils are divided into two groups according to the position intervals, and the coils in the groups are connected in series when connected, and the two coil windings are connected in parallel after passing through the rectifier bridge;

[0012] The lower cylinder comprises: spindle cylinder 2, track 3, fan blade 2, track 4, permanent magnet, nylon membrane, PTFE membrane; spindle cylinder 2 is a hollow spindle body whose size matches the hollow part of spindle cylinder 2, and spindle cylinder 1 is coaxially sleeved on the outer periphery of spindle cylinder 2; fan blade 2 is coaxially fixed to the bottom of spindle cylinder 2, and fan blade 2 comprises a plurality of blades twisted in the same direction, and the twisting direction of the blades is opposite to that of fan blade 1; a plurality of tracks 3 are arranged on the inner wall of spindle cylinder 2, which are circumferentially encircled head to tail , each blade of the second fan blade is provided with a plurality of tracks four; a plurality of fan-shaped nylon membranes and PTFE membranes are evenly attached to the outer wall of the second spindle tube in a circumferential direction, the number of nylon membranes and PTFE membranes are the same and the size is the same, the two membranes are staggered and attached, and a gap two is left between two adjacent membranes; a plurality of permanent magnet slots are evenly opened in a circumferential direction inside the wall of the second spindle tube, a permanent magnet is installed in each permanent magnet slot, the permanent magnets are staggered in NS arrangement according to the position, and the ratio of the number of permanent magnets to the number of coils is 1:1;

[0013] Grid-shaped copper electrodes are laid inside the track one, track two, track three and track four. The surface material of the ball is FEP, which is installed in the track one, track two, track three and track four respectively and can slide and roll therein.

[0014] Furthermore, the track one, track two, track three and track four are all wavy.

[0015] Furthermore, the fan blade 1 includes three blades, the three blades converge on a central axis, and the central axis is sleeved and installed on the base; the fan blade 2 includes three blades, the three blades converge on a central axis, and the central axis is sleeved and installed on the base.

[0016] Furthermore, the pitch angle of each blade of Blade 1 and Blade 2 is 0°, and the projected area angle is 60°.

[0017] Furthermore, the power management circuit includes: a rectifier and filter circuit, an energy storage unit, an overvoltage protection unit, and a voltage stabilization unit;

[0018] The rectification and filtering unit includes a rectification circuit and a filter, wherein the rectification circuit is used to convert alternating current into direct current; and the filter is used to reduce ripples in the current and generate an output closer to an ideal direct current;

[0019] The energy storage unit is used to store the direct current converted by the rectification and filtering unit;

[0020] The overvoltage protection unit is used to protect the circuit and release the voltage when the voltage exceeds the set threshold;

[0021] The voltage stabilizing unit is used to ensure that the output voltage of the power management circuit is always close to the set value.

[0022] The beneficial effects of the present invention are:

[0023] (1) The system of the present invention adopts friction nanogenerator and electromagnetic generator technology, which gets rid of the dependence on batteries and solves the problems of maintenance and battery replacement, thereby ensuring the continuous and stable operation of the bridge sensing system.

[0024] (2) In the system of the present invention, the hybrid energy collection device adopts a coaxially sleeved and rotatable cone cylinder 1, cone cylinder 2 or spindle cylinder 1, spindle cylinder 2. The cone-shaped or spindle-shaped design can not only reduce air resistance in the rotating state, but also effectively overcome the problem of water accumulation in the hybrid energy collection device during rainy and snowy days.

[0025] (3) In the system of the present invention, multiple circumferential tracks connected end to end are opened on the outer wall of the first cone tube, the inner wall of the second cone tube, or the outer wall of the first spindle tube, the inner wall of the second spindle tube of the hybrid energy collection device. When the wind speed is high and the rotation speed is fast, the balls can move continuously based on inertia and wind force, thereby improving the power generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural block diagram of a bridge self-powered displacement-acceleration sensing system based on hybrid energy harvesting in an embodiment of the present invention.

[0027] Figure 2 It is a schematic diagram of the structure of the hybrid energy collection device in Example 1 of the present invention.

[0028] Figure 3 It is a schematic diagram of the upper cylinder structure of the hybrid energy collection device in Example 1 of the present invention.

[0029] Figure 4 It is a schematic diagram of the lower tube structure of the hybrid energy collection device in Example 1 of the present invention.

[0030] Figure 5 It is a cross-sectional view of the lower tube structure of the hybrid energy collection device in Example 1 of the present invention.

[0031] Figure 6 It is a schematic diagram of the cycle of the first type of friction nanogenerator generating alternating current in an embodiment of the present invention, which is divided into four processes and repeats repeatedly, among which (a) is process one, (b) is process two, (c) is process three, and (d) is process four.

[0032] Figure 7 It is a schematic diagram of the cycle of the second type of friction nanogenerator generating alternating current in an embodiment of the present invention, which is divided into four processes and repeats repeatedly, among which (a) is process one, (b) is process two, (c) is process three, and (d) is process four.

[0033] Figure 8 It is a schematic diagram of the structure of the hybrid energy collection device in Example 2 of the present invention.

[0034] Fig. 9 It is a schematic diagram of the upper cylinder structure of the hybrid energy collection device in Example 2 of the present invention.

[0035] Fig.10 It is a cross-sectional view of the upper cylinder structure of the hybrid energy collection device in Example 2 of the present invention.

[0036] Fig.11 It is a schematic diagram of the lower tube structure of the hybrid energy collection device in Example 2 of the present invention.

[0037] Fig.12 It is a cross-sectional view of the lower tube structure of the hybrid energy collection device in Example 2 of the present invention.

[0038] In the figure, upper cylinder 1, conical cylinder 1-1, track 1-2, fan blade 1-3, track 2 1-4, cone top 1-5, coil 1-6, grid copper electrode 1-7, gap 1-8, polyester fiber hair 1-9, spindle cylinder 1-10; lower cylinder 2, conical cylinder 2-1, track 3 2-2, fan blade 2-3, track 4 2-4, cone bottom 2-5, permanent magnet 2-6, nylon membrane 2-7, PTFE (polytetrafluoroethylene) membrane 2-8, gap 2 2-9, spindle cylinder 2 2-10; base 3, truncated table 3-1, support rod 3-2; ball 4. DETAILED DESCRIPTION

[0039] The present invention will be described in detail below according to the accompanying drawings and preferred embodiments, and the purpose and effect of the present invention will become more clear. The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] like Figure 1 As shown, a self-powered displacement-acceleration sensing system for bridges based on hybrid energy harvesting includes: a hybrid energy harvesting device, a power management circuit, a sensor unit, and a micro-control unit. The hybrid energy harvesting device collects clean energy based on electromagnetic generators and friction nanogenerators, that is, wind energy is obtained from the bridge, converted into electrical energy, and then passed through the power management circuit to output a DC voltage to power the sensor unit and the micro-control unit. The micro-control unit then transmits the data monitored by the sensor unit, and finally realizes the self-powering of the system.

[0041] The power management circuit includes: a rectifier filter circuit, an energy storage unit, an overvoltage protection unit, and a voltage stabilization unit. The rectifier filter unit includes a rectifier circuit and a filter. After the rectifier circuit converts alternating current (AC) into direct current (DC), the pulse is smoothed by the filter to reduce the ripple in the current, thereby producing an output that is closer to the ideal DC. The energy storage unit is used to store the DC converted by the rectifier filter unit. The overvoltage protection unit is used to protect subsequent circuit devices and release the voltage when the voltage exceeds the threshold. The voltage stabilization unit ensures that the output voltage of the power management circuit is always near a set value regardless of how the input voltage or load conditions change.

[0042] The sensing unit includes acceleration sensors and displacement sensors, which are used to display the acceleration and displacement of key nodes of the bridge cables and characterize the health status of the bridge structure.

[0043] The hybrid energy harvesting device includes an electromagnetic generator (EMG) unit and a triboelectric nanogenerator (TENG) unit, and structurally includes an upper cylinder 1, a lower cylinder 2, a base 3, and a ball 4. The base 3 includes a truncated cone 3-1 and a support rod 3-2, and the support rod 3-2 is fixedly connected to the center of the upper surface of the truncated cone 3-1; in this embodiment, the height of the truncated cone 3-1 is 5 cm, the diameter of the upper bottom surface is 4 cm, and the diameter of the lower bottom surface is 32 cm. The diameter of the support rod 3-2 is 1 cm and the height is 70 cm. The upper cylinder 1 and the lower cylinder 2 are coaxially sleeved on the support rod 3-1, and the upper cylinder 1 is sleeved on the outer periphery of the lower cylinder 2. Both the upper cylinder 1 and the lower cylinder 2 can rotate around the support rod 3-2. The surface material of the ball 4 is FEP (Fluorinated Ethylene Propylene).

[0044] Example 1

[0045] like Figure 2 As shown in the figure, as one embodiment, the upper cylinder 1 and the lower cylinder 2 are both in a cone-shaped + fan blade structure as a whole, specifically as follows:

[0046] like Figure 3 As shown, the upper cylinder 1 includes: a cone cylinder 1-1, a track 1-2, a fan blade 1-3, a track 2 1-4, a cone top 1-5, a coil 1-6, a grid-shaped copper electrode 1-7, a gap 1-8, and polyester fiber wool 1-9. The cone cylinder 1-1 is a hollow cone with an opening at the bottom. It is designed to be conical, which can not only reduce air resistance in a rotating state, but also effectively overcome the problem of water accumulation in the hybrid energy collection device during rainy and snowy days. The fan blade 1-3 is fixedly connected to the cone top 1-5 of the cone cylinder 1-1. The fan blade 1-3 includes multiple blades. The central axis of the fan blade 1-3 is sleeved and installed on the support rod 3-2. The fan blade 1-3 can rotate around the axis driven by the wind. A plurality of circumferentially connected tracks 1-2 are provided on the outer wall of the conical cylinder 1-1, and the tracks 1-2 are wavy; a plurality of wavy tracks 1-4 are provided on the fan blade 1-3; grid-shaped copper electrodes 1-7 are respectively laid in the tracks 1-2 and 1-4, and balls 4 are respectively installed in the tracks 1-2 and 1-4, and can slide or roll in the tracks.

[0047] A plurality of fan-shaped flexible PCBs, i.e., grid-shaped copper electrodes 1-7, are attached to the inner wall of the conical cylinder 1-1. A gap 1-8 is set between two adjacent grid-shaped copper electrodes 1-7. A gap 1-8 is arranged every other gap 1-8. Polyester fiber wool 1-9 is arranged in the gap 1-8 to increase friction. A plurality of coil slots are evenly arranged in the circumferential direction of the inner wall of the conical cylinder 1-1. The opening of the coil slot is located on the bottom surface of the conical cylinder 1-1, which is used to locate, install and protect the coil 1-6. The coils 1-6 are placed in sequence in the same direction (clockwise or counterclockwise) and divided into two groups according to the position interval (taking the circumferentially evenly arranged 6 coils 1-6 as an example, divided into two groups A and B, and the coils 1-6 are arranged in the circumferential order: A, B, A, B, A, B). When connected, the coils 1-6 in the group are connected in series, and then after passing through the rectifier bridge, the two windings are connected in parallel.

[0048] In this embodiment, the inner diameter of the cone cylinder 1-1 is 20 cm, the outer diameter is 24 cm, the thickness is 2 cm, and the height is 16.7 cm. The blade length of the fan blade 1-3 is 9.5 cm, the height is 20 cm, the pitch angle is 0°, the projected area angle is 60°, the blade thickness is 0.05 cm, and the number of blades is 3. The diameter of the ball 4 installed in the track 1-2 is 1 cm, and the diameter of the ball 4 installed in the track 2 1-4 is 0.5 cm. Four pairs of pole-sector-shaped grid copper electrodes 1-7 are attached to the inner wall of the cone cylinder 1-1. The arc length of the pole-sector-shaped grid copper electrode 1-7 is (2.25π-0.5) cm, and the length is 15 cm. There are eight gaps 1-8 with a width of 0.5 cm between the grid copper electrodes 1-7, and the four gaps 1-8 are spaced apart with polyester fiber wool 1-9 with a width of 0.5 cm. There are 12 coil slots evenly arranged in the circumferential direction on the inner wall of the conical cylinder 1-1, and 12 coils 1-6 are installed correspondingly. The coils 1-6 are 2 cm long, 0.8 cm wide, 21 cm high, and have a wire diameter of 0.1 mm. The 6 coils 1-6 spaced apart are connected in series as a group and connected in parallel with another group after passing through a rectifier bridge.

[0049] like Figure 4 and Figure 5As shown, the lower cylinder 2 includes: a conical cylinder 2-1, a track 3-2, a fan blade 2-3, a track 4-4, a cone bottom 2-5, a permanent magnet 2-6, a nylon membrane 2-7, a PTFE membrane 2-8, and a gap 2-9. The conical cylinder 2-1 is also a hollow cone with an opening at the bottom, which is compatible with the conical cylinder 1-1, so that the conical cylinder 1-1 can be well sleeved on the outer periphery of the conical cylinder 2-1. The center of the bottom of the conical cylinder 2-1 (i.e., the cone bottom 2-5) is fixedly connected to the central axis of the fan blade 2-3; the fan blade 2-3 includes multiple blades, and the torsion direction is opposite to that of the fan blade 1-3; the central axis of the fan blade 2-3 is sleeved and installed on the support rod 3-2, and the fan blade 2-3 can rotate around the axis driven by the wind, and the rotation direction is opposite to that of the fan blade 1-3 of the upper cylinder 1, and will not interfere with the conical cylinder 2-1 when rotating. A plurality of circumferentially circumferential tracks 3-2 are provided on the inner wall of the conical cylinder 2-1, and the tracks 3-2 are wavy; a plurality of wavy tracks 4-2-4 are provided on the fan blade 2-3; grid-shaped copper electrodes 1-7 are respectively laid in the tracks 3-2 and 4-2-4, and balls 4 are respectively installed in the tracks 3-2 and 4-2-4, and can slide or roll in the tracks.

[0050] A plurality of fan-shaped nylon films 2-7 and PTFE films 2-8 are attached to the outer wall of the conical cylinder 2-1. The number and size of the nylon films 2-7 and PTFE films 2-8 are the same. The two films are attached alternately, and a gap 2-9 is left between two adjacent films. A plurality of permanent magnet slots are evenly opened in the circumferential direction of the inner wall of the conical cylinder 2-1. The opening of the permanent magnet slot is located at the bottom surface of the conical cylinder 2-1, which is used to locate, install and protect the permanent magnet 2-6. The permanent magnet 2-6 is placed in sequence in the same direction (clockwise or counterclockwise), and arranged in a staggered manner according to the position. The ratio of the number of permanent magnets 2-6 to the number of coils 1-6 is 1:1.

[0051] In the present embodiment, the inner diameter of the cone cylinder 2-1 is 14cm, the outer diameter is 18cm, the thickness is 2cm, and the height is 18cm. The blade length of the blade 2-3 is 8.5cm, the height is 20cm, the pitch angle is 0°, the projected area angle is 60°, the blade thickness is 0.05cm, and the number of blades is 3. The diameter of the ball 4 installed in the track 3 2-2 is 1cm, and the diameter of the ball 4 installed in the track 4 2-4 is 0.5cm. There are 4 pieces of nylon membrane 2-7 and PTFE membrane 2-8 respectively, and the arc length of nylon membrane 2-7 and PTFE membrane 2-8 is (2π-0.5)cm, the radius is 15cm, and the width of gap 2-9 is 0.5cm. There are 12 permanent magnet slots opened, corresponding to the installation of 12 permanent magnets 2-6, and the permanent magnet 2-6 is 2cm long, 0.8cm wide, and 20cm high.

[0052] When the hybrid energy collection device is working, when the wind caused by natural wind or the disturbance of airflow after the vehicle passes by blows toward the hybrid energy collection device, due to the action of wind force, the blades 1-3 of the upper cylinder 1 and the blades 2-3 of the lower cylinder 2 rotate in opposite directions, thereby driving the cone cylinder 1-1 and cone cylinder 2-1 fixed thereto to rotate in opposite directions. Taking the counterclockwise rotation of the upper cylinder 1 and the clockwise rotation of the lower cylinder 2 as an example, the upper cylinder 1 drives the coil 1-6, the grid copper electrode 1-7 and the polyester fiber wool 1-9 to rotate counterclockwise, and the lower cylinder 2 drives the permanent magnet 2-6, the PTFE membrane 2-8 and the nylon membrane 2-7 to move clockwise. Since the rotation directions are opposite, it is equivalent to doubling the rotation speed of the overall device under the same wind speed, and the power generation efficiency is improved.

[0053] The relative rotation between the coil 1-6 and the permanent magnet 2-6 can realize EMG power generation. The principle is as follows: the permanent magnet 2-6 with alternating polarity rotates to generate an alternating magnetic field. According to Lenz's law, the induced current generated in the coil 1-6 always resists the change of magnetic flux. When the magnet is close to the coil 1-6, the coil 1-6 generates an induced current in one direction to resist the increase of magnetic flux density. When the magnet is away from the coil 1-6, the coil 1-6 generates an induced current in the opposite direction to resist the decrease of magnetic flux density. Due to the alternating polarity of the permanent magnet 2-6, the coil 1-6 with alternating poles is staggered into two groups, and the current direction of each group is opposite. When the permanent magnet 2-6 rotates continuously, the coil 1-6 generates continuous alternating current.

[0054] The relative rotation of the above-mentioned grid-shaped copper electrode 1-7, polyester fiber wool 1-9, PTFE membrane 2-8, and nylon membrane 2-7 can realize the first type of TENG power generation, and the principle is as follows: Figure 6 As shown, the three materials, nylon membrane 2-7, PTFE membrane 2-8 and polyester fiber hair 1-9, have different abilities to gain or lose electrons. Among them, PTFE membrane 2-8 is most likely to gain electrons and show electronegativity, nylon membrane 2-7 is most likely to lose electrons and show electronegativity, and the ability of polyester fiber hair 1-9 to gain or lose electrons is between the two. Therefore, when nylon membrane 2-7 and PTFE membrane 2-8 are rubbed with polyester fiber hair 1-9 together, polyester fiber hair 1-9 increases charge transfer, so that PTFE membrane 2-8 and nylon membrane 2-7 both carry equal and opposite charges, and gradually tend to saturation during friction. However, the charges on PTFE membrane 2-8 and nylon membrane 2-7 will not disappear or transfer in a short time. At this time, the electrons of the grid copper electrode 1-7 are driven based on charge induction, and the current flows from high potential to low potential. After connecting to the external circuit, alternating current is formed. This type of power generation structural design utilizes polyester fiber hair 1-9 to indirectly rub the positive and negative friction layers (nylon membrane 2-7 and PTFE membrane 2-8), thereby increasing space utilization and potential difference, thereby increasing electron transfer. In addition, the use of polyester fiber hair 1-9 reduces the large-area contact of the friction layer and reduces friction resistance, making the structure have better conversion efficiency than existing structures under the same external force drive.

[0055] When the upper cylinder 1 and the lower cylinder 2 rotate in opposite directions, the ball 4 with the FEP surface slides on the track 1-2, track 2-4, track 3-2-2 and track 4-2-4 on which the grid copper electrodes 1-7 are laid due to inertia, so that irregular alternating current can be derived from the track, and because the track 1-2 and track 3-2-2 are wavy tracks with no end point restrictions, when the wind speed is high and the rotation speed is fast, the ball 4 will not always accumulate on one side when the wind is strong, and the ball 4 can move continuously based on inertia and wind force, so that the movement of the ball 4 is freer and unrestricted at any wind speed.

[0056] The ball 4 moves relative to the track on which the grid-shaped copper electrodes 1-7 are laid, which can realize the second type of TENG power generation. The principle is as follows: Figure 7 As shown, the grid copper electrode 1-7 is laid on track 1-2, track 2-4, track 3-2-2, and track 4-4. At this time, the grid copper electrode 1-7 serves as both a conductive layer and a friction layer. FEP and copper have different abilities to gain and lose electrons. FEP is more likely to lose electrons, while copper is more likely to gain electrons. Therefore, after the ball 4 and the grid copper electrode 1-7 are rubbed, the two carry equal and opposite charges. The charge on the FEP will not disappear or transfer in a short time. When the ball 4 rotates with the lower cylinder 2, the grid copper electrode 1-7 induces unequal positive charges. After connecting to the external circuit, in order to ensure the potential balance, electrons flow in the external circuit, thereby forming alternating current. The structural design of this type of power generation makes full use of the space on the surface of the structure, increases a part of the output, and greatly increases the space utilization rate.

[0057] The electrical signals generated by the two types of TENG and EMG are integrated, converted from AC to DC and improved in quality through the rectifier and filter units, and the collected electrical energy is stored in the energy storage unit. The output voltage amplitude is then controlled by the voltage stabilizing unit. During this process, the overvoltage protection unit always protects the circuit to ensure the normal operation of the system displacement-acceleration sensor.

[0058] Example 2

[0059] like Figure 8 As shown in the figure, as one embodiment, the upper tube 1 and the lower tube 2 are both in a spindle-shaped + fan blade structure as a whole, as follows:

[0060] like Fig. 9 , 10As shown, the upper cylinder 1 includes: a spindle cylinder 1-10, a track 1-2, a fan blade 1-3, a track 2 1-4, a cone top 1-5, a coil 1-6, a grid copper electrode 1-7, a gap 1-8, and polyester fiber hair 1-9. The spindle cylinder 1-10 is a hollow spindle body. This appearance design can not only reduce air resistance in the rotating state, but also effectively overcome the problem of water accumulation in the hybrid energy collection device during rainy and snowy days. The spindle body of the spindle cylinder 1-10 is composed of a hollow cone in the upper and lower parts. The hollow cone structure of the upper part and the hollow cone structure of the lower part are the same as the cone cylinder 1-1 in Example 1, and the bottom of the hollow cone of the upper part is the same size as the bottom of the hollow cone of the lower part; when installed, the bottoms of the two cones are opposite (each coil slot is opposite one by one) and are fixedly connected. The fan blade 1-3 is fixedly connected to the cone top 1-5 of the hollow cone on the upper part of the spindle tube 1-10, and the fan blade 1-3 can drive the spindle tube 1-10 to rotate when it rotates.

[0061] like Fig.11 , 12 As shown, the lower cylinder 2 includes: spindle cylinder 2-10, track 3-2, fan blade 2-3, track 4-4, cone bottom 2-5, permanent magnet 2-6, nylon membrane 2-7, PTFE membrane 2-8, gap 2-9, spindle cylinder 2-10. Spindle cylinder 2-10 is also a hollow spindle body, which is composed of two hollow cones, the upper part and the lower part. The hollow cone structure of the upper part and the hollow cone structure of the lower part are the same as those of the cone cylinder 2-1 in Example 1, and the bottom of the upper part and the bottom of the hollow cone are the same size; when installed, the bottoms of the two cones are opposite (the permanent magnet slots are opposite one by one) and fixedly connected. The size of the second spindle cylinder 2-10 is slightly smaller than the inner size of the first spindle cylinder 1-10, and the nylon membrane 2-7 and PTFE membrane 2-8 on the outer surface of the second spindle cylinder 2-10 can contact and generate friction with the grid-shaped copper electrode 1-7 on the inner surface of the first spindle cylinder 1-10. The second fan blade 2-3 is fixedly connected to the cone top 1-5 of the hollow cone at the lower part of the second spindle cylinder 2-10, and the second fan blade 2-3 can drive the second spindle cylinder 2-10 to rotate when it rotates.

[0062] When the hybrid energy harvesting device is working, the blade 1-3 and the blade 2-3 rotate in the opposite direction, driving the spindle tube 1-10 and the spindle tube 2-10 fixed thereto to rotate in the opposite direction, thereby driving the coil 1-6 and the permanent magnet 2-6 to rotate relative to each other, realizing EMG power generation; the grid copper electrode 1-7, the polyester fiber hair 1-9 and the nylon membrane 2-7, and the PTFE membrane 2-8 rotate relative to each other, realizing the first type of TENG power generation; the ball 4 moves relative to the track on which the grid copper electrode 1-7 is laid, realizing the second type of TENG power generation. Then, the electrical signals generated by the two types of TENG and EMG are integrated, and the AC to DC conversion and quality improvement are performed through the rectifier and filter unit, and the collected electrical energy is stored by the energy storage unit, and then the output voltage amplitude is controlled by the voltage stabilizing unit. In this process, the overvoltage protection unit always protects the circuit to ensure the normal operation of the system displacement-acceleration sensor.

[0063] In summary, the self-powered displacement-acceleration sensing system for bridges based on hybrid energy harvesting proposed in the present invention is independent of external power supplies and can be self-powered, which greatly improves the reliability and sustainability of bridge health monitoring. The present invention cleverly utilizes the environmental resources of the bridge itself, especially the natural wind force and the wind force generated by the airflow disturbance caused by vehicles running on the bridge. These wind forces are captured by the energy conversion device in the system, that is, the hybrid energy harvesting device, and converted into electrical energy to power the displacement sensor and the acceleration sensor. The system of the present invention can continuously track the displacement and acceleration changes of key positions of the bridge, collect data in real time to protect the safety status of the bridge and provide early warning. The implementation of this system can effectively delay the damage caused by aging of the bridge structure, extend the service life of the bridge, and significantly reduce the resources and costs generated by frequent reconstruction or extensive repairs.

[0064] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A bridge self-powered displacement-acceleration sensing system based on hybrid energy harvesting, characterized in that: include: Hybrid energy harvesting device, power management circuit, sensor unit, micro-control unit; The hybrid energy collection device is used to convert wind energy into electrical energy, and the power management circuit is used to convert the alternating current generated by the hybrid energy collection device into a direct current voltage to power the sensor unit and the micro-control unit; The sensing unit includes a displacement sensor and an acceleration sensor, and the micro-control unit is used to transmit data of the sensing unit; The hybrid energy collector comprises: an upper cylinder, a lower cylinder, a base, and a ball bearing; the upper cylinder and the lower cylinder are coaxially sleeved on the base and can rotate around the central axis; The upper cylinder comprises: a conical cylinder 1, a track 1, a fan blade 1, a track 2, a coil, a grid-shaped copper electrode, and polyester fiber wool; the conical cylinder 1 is a hollow cone with an opening at the bottom, the fan blades are coaxially fixed to the top of the cone, and the fan blade 1 comprises a plurality of blades twisted in the same direction; a plurality of tracks 1 surrounding the circumference end to end are arranged on the outer wall of the conical cylinder 1, and a plurality of tracks 2 are arranged on each blade of the fan blade 1; a fan-shaped grid-shaped copper electrode is attached to the inner wall of the conical cylinder 1, and a plurality of gaps 1 are evenly arranged in the circumference of the grid-shaped copper electrode, and each gap 1 is arranged in each gap, and polyester fiber wool is arranged in the gap 1; a plurality of coil slots are evenly arranged in the circumference of the inner wall of the conical cylinder 1, and a coil is installed in each coil slot, and the coils are divided into two groups according to the position intervals, and the coils in the group are connected in series when connected, and the two coil windings are connected in parallel after passing through the rectifier bridge; The lower cylinder comprises: a second cone cylinder, a third track, a second blade, a fourth track, a permanent magnet, a nylon membrane, and a PTFE membrane; the second cone cylinder is a hollow cone with an opening at the bottom, and a cone cylinder is coaxially sleeved on the outer periphery of the second cone cylinder, and the size of the second cone cylinder is adapted to the hollow part of the first cone cylinder; the bottom center of the second cone cylinder is coaxially fixedly connected to the second blade, and the second blade comprises a plurality of blades twisted in the same direction, and the twisting direction of the blades is opposite to that of the first blade; a plurality of circumferential head and tail rings are arranged on the inner wall of the second cone cylinder The outer wall of the conical cylinder 2 is uniformly attached with a plurality of fan-shaped nylon membranes and PTFE membranes in a circumferential direction. The number and size of the nylon membranes and PTFE membranes are the same, and the two membranes are staggered and attached, and a gap 2 is left between two adjacent membranes. A plurality of permanent magnet slots are uniformly opened in the circumferential direction of the inner wall of the conical cylinder 2, and a permanent magnet is installed in each permanent magnet slot. The permanent magnets are staggered in NS according to the position, and the ratio of the number of permanent magnets to the coil is 1:

1. Grid-shaped copper electrodes are laid inside the track one, track two, track three and track four. The surface material of the ball is FEP, which is installed in the track one, track two, track three and track four respectively and can slide and roll therein.

2. A bridge self-powered displacement-acceleration sensing system based on hybrid energy harvesting, characterized in that: include: Hybrid energy harvesting device, power management circuit, sensor unit, micro-control unit; The hybrid energy collection device is used to convert wind energy into electrical energy, and the power management circuit is used to convert the alternating current generated by the hybrid energy collection device into a direct current voltage to power the sensor unit and the micro-control unit; The sensing unit includes a displacement sensor and an acceleration sensor, and the micro-control unit is used to transmit data of the sensing unit; The hybrid energy collector comprises: an upper cylinder, a lower cylinder, a base, and a ball bearing; the upper cylinder and the lower cylinder are coaxially sleeved on the base and can rotate around the central axis; The upper cylinder comprises: a spindle cylinder 1, a track 1, a fan blade 1, a track 2, a coil, a grid-shaped copper electrode, and polyester fiber wool; the spindle cylinder 1 is a hollow spindle; the fan blades are coaxially fixedly connected to the top thereof, and the fan blade 1 comprises a plurality of blades twisted in the same direction; a plurality of tracks 1 which are circumferentially encircled end to end are provided on the outer wall of the spindle cylinder 1, and a plurality of tracks 2 are provided on each blade of the fan blade 1; a fan-shaped grid-shaped copper electrode is attached to the inner wall of the spindle cylinder 1, and a plurality of gaps 1 are uniformly provided on the grid-shaped copper electrode in the circumferential direction, and each gap 1 is provided between each gap 1, and polyester fiber wool is arranged in the gap 1; a plurality of coil slots are uniformly provided on the inner wall of the spindle cylinder 1 in the circumferential direction, and a coil is installed in each coil slot, and the coils are divided into two groups according to the position intervals, and the coils in the groups are connected in series when connected, and the two coil windings are connected in parallel after passing through the rectifier bridge; The lower cylinder comprises: spindle cylinder 2, track 3, fan blade 2, track 4, permanent magnet, nylon membrane, PTFE membrane; spindle cylinder 2 is a hollow spindle body whose size matches the hollow part of spindle cylinder 2, and spindle cylinder 1 is coaxially sleeved on the outer periphery of spindle cylinder 2; fan blade 2 is coaxially fixed to the bottom of spindle cylinder 2, and fan blade 2 comprises a plurality of blades twisted in the same direction, and the twisting direction of the blades is opposite to that of fan blade 1; a plurality of tracks 3 are arranged on the inner wall of spindle cylinder 2, which are circumferentially encircled head to tail , each blade of the second fan blade is provided with a plurality of tracks four; a plurality of fan-shaped nylon membranes and PTFE membranes are evenly attached to the outer wall of the second spindle tube in a circumferential direction, the number of nylon membranes and PTFE membranes are the same and the size is the same, the two membranes are staggered and attached, and a gap two is left between two adjacent membranes; a plurality of permanent magnet slots are evenly opened in a circumferential direction inside the wall of the second spindle tube, a permanent magnet is installed in each permanent magnet slot, the permanent magnets are staggered in NS arrangement according to the position, and the ratio of the number of permanent magnets to the number of coils is 1:1; Grid-shaped copper electrodes are laid inside the track one, track two, track three and track four. The surface material of the ball is FEP, which is installed in the track one, track two, track three and track four respectively and can slide and roll therein.

3. The bridge self-powered displacement-acceleration sensing system based on hybrid energy harvesting according to claim 1 or 2, characterized in that: The track one, track two, track three and track four are all in a wave shape.

4. The bridge self-powered displacement-acceleration sensing system based on hybrid energy harvesting according to claim 1 or 2, characterized in that: The fan blade 1 includes three blades, which converge on a central axis, and the central axis is sleeved and mounted on the base; the fan blade 2 includes three blades, which converge on a central axis, and the central axis is sleeved and mounted on the base.

5. The bridge self-powered displacement-acceleration sensing system based on hybrid energy harvesting according to claim 1 or 2, characterized in that: The pitch angle of each blade of the fan blade 1 and the fan blade 2 is 0°, and the projected area angle is 60°.

6. The bridge self-powered displacement-acceleration sensing system based on hybrid energy harvesting according to claim 1 or 2, characterized in that: The power management circuit includes: a rectifier and filter circuit, an energy storage unit, an overvoltage protection unit, and a voltage stabilization unit; The rectification and filtering unit includes a rectification circuit and a filter, wherein the rectification circuit is used to convert alternating current into direct current; and the filter is used to reduce ripples in the current and generate an output closer to an ideal direct current; The energy storage unit is used to store the direct current converted by the rectification and filtering unit; The overvoltage protection unit is used to protect the circuit and release the voltage when the voltage exceeds the set threshold; The voltage stabilizing unit is used to ensure that the output voltage of the power management circuit is always close to the set value.

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