Bridge self-powered strain sensing system based on friction nanogeneration and electromagnetic generation

Abstract

The invention discloses a bridge self-powered strain sensing system based on friction nano-power generation and electromagnetic power generation, wherein a wind energy conversion device converts wind energy into electric energy and then converts it into direct current through a power management circuit to power the remaining units; the wind energy conversion device comprises a ball with a surface of FEP, an upper cylinder and a lower cylinder which are coaxially sleeved and rotatable, an upper fan blade is fixedly connected to the outer wall of the upper cylinder, and the cylinder and the fan blade of the lower cylinder are fixedly connected through ribs, and the upper and lower fan blades are twisted in opposite directions; a plurality of inclined rails are provided on the outer wall of the upper cylinder, the inner wall of the lower cylinder, and the upper and lower fan blades to accommodate the ball; a grid-shaped copper electrode is attached to the inner wall of the upper cylinder at intervals in the circumferential direction, and polyester fiber wool is arranged at intervals in the gap; a plurality of coils are embedded in the circumferential direction of the upper cylinder, and a plurality of permanent magnets are embedded in the circumferential direction of the lower cylinder; a plurality of nylon films and PTFE films of the same number are attached to the outer wall of the lower cylinder at uniform and staggered intervals in the circumferential direction. The invention realizes the self-power supply of the strain sensing system, and ensures the continuous real-time monitoring of the strain of the bridge structure.

Description

Technical Field

[0001] The present invention relates to the fields of wind power generation and environmental energy development, and in particular to a bridge self-powered strain sensing system based on friction nano-power generation and electromagnetic power generation. Background Art

[0002] As an important transportation infrastructure that connects geographical space and facilitates the flow of people and materials, the safe and stable operation of bridges is of vital importance. The safety of bridges is not only directly related to the safety of people's lives and property, but also affects the efficiency of economic activities and social operations. Over time, bridges will gradually show signs of structural damage and fatigue due to material aging, environmental erosion, overload operation, etc. In addition, increased traffic volume and possible overloading will accelerate this process and increase the risk of structural failure. In this context, real-time monitoring and health status assessment of bridges are particularly important.

[0003] In order to solve the problem of real-time monitoring of bridges due to structural aging, key parts such as piers, abutments, beams, bridge decks, bearings, cables and hangers, which have to withstand significant strain and deformation, need to be installed with strain sensors. Therefore, strain sensors play a core role in the bridge health monitoring system, accurately measuring the strains borne by the bridge structure in daily use and providing real-time data for engineers to analyze. These monitoring data can reveal the strain distribution of various parts of the bridge and the potential development trend of fatigue cracks, providing a scientific basis for bridge maintenance; by regularly analyzing these data, structural weaknesses and signs of damage can be discovered in time, so that maintenance or reinforcement measures can be taken before the problem expands into a serious safety hazard. Commonly used strain sensors are powered by chemical batteries, which are difficult to repair and replace. During the process of replacing or repairing the strain sensor, the monitoring system may fail for part of the time, resulting in a staged paralysis of the monitoring system during maintenance and replacement. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention proposes a bridge self-powered strain sensing system based on friction nano-power generation and electromagnetic power generation.

[0005] The specific technical solutions are as follows:

[0006] A bridge self-powered strain sensing system based on friction nano-power generation and electromagnetic power generation, comprising: a wind energy conversion device, a power management circuit, a sensor unit, and a micro-control unit; the wind energy conversion device converts wind energy into electrical energy, and then passes through the power management circuit to convert it into a DC voltage to power the sensor unit and the micro-control unit, the sensor unit is a strain sensor, and the micro-control unit is used to transmit data of the sensor unit; the wind energy conversion device 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 the central axis, and the upper cylinder is sleeved on the outer periphery of the lower cylinder; the surface of the ball is made of FEP;

[0007] The upper cylinder comprises: an upper cylinder, an upper inclined rail, an upper rib, an upper fan blade, a grid-shaped copper electrode, a gap one, polyester fiber wool, and a coil; the upper cylinder is a tubular structure, which is fixedly connected to the central axis through the upper rib, and the central axis is sleeved on the base; the upper fan blade is fixedly connected to the outer wall of the upper cylinder evenly in the circumferential direction, and the upper fan blade comprises a plurality of blades twisted in the same direction; a plurality of upper inclined rails are respectively provided on the outer wall of the upper cylinder and the outer surface of the upper fan blade, and a grid-shaped copper electrode is laid in the upper inclined rail, and the ball slides or rolls in the upper inclined rail; the grid-shaped copper electrode is attached to the inner wall of the upper cylinder, and a plurality of gaps one are evenly provided in the circumferential direction of the grid-shaped copper electrode, and each gap one is arranged, and polyester fiber wool is arranged in the gap one; a plurality of coil slots are evenly provided in the circumferential direction of the inner wall of the upper cylinder, and a coil is installed in each coil slot, and the coils are divided into two groups according to the position interval, and the coils in the group are connected in series when connected, and the two groups of coils are connected in parallel after passing through the rectifier bridge;

[0008] The lower cylinder comprises: a lower cylinder, a lower inclined rail, a lower rib, a lower blade, a nylon membrane, a PTFE membrane, a gap 2, and a permanent magnet; the lower cylinder is a tubular structure, and its outer diameter is smaller than the inner diameter of the upper cylinder, and the upper cylinder is sleeved on the outer circumference of the lower cylinder; the lower surface of the lower cylinder is fixedly connected to the lower blade through the lower rib, and the torsion direction of the lower blade is opposite to that of the upper blade; a plurality of lower inclined rails are respectively provided on the upper and lower blades of the inner wall of the lower cylinder, and a grid-shaped copper electrode is laid in the lower inclined rail, and the ball slides or rolls in the lower inclined rail; a plurality of pieces of nylon membrane and PTFE membrane of the same number are evenly attached circumferentially on the outer wall of the lower cylinder, and the nylon membrane and the PTFE membrane are attached alternately at intervals; the inner wall of the lower cylinder is evenly provided with permanent magnet slots of the same number as the coil slots, and a permanent magnet is installed in each permanent magnet slot, and the permanent magnets are arranged in an NS staggered manner.

[0009] Furthermore, there are three upper ribs, one end of which intersects with the intersection being located at the central axis of the upper cylinder, and the other end is fixedly connected to the outer periphery of the upper surface of the upper cylinder, and the angle between adjacent upper ribs is 120°; the upper fan blade includes three blades, one blade of the upper fan blade is fixedly connected above each upper rib, the blades intersect at the central axis and a through hole is provided at the central axis for being sleeved on the base;

[0010] There are three lower ribs, one end of the three lower ribs intersect and the intersection is located at the central axis of the lower cylinder, the other end is fixedly connected to the outer periphery of the lower surface of the lower cylinder, and the angle between adjacent lower ribs is 120°; the lower fan blade includes three blades, a blade of the lower fan blade is fixedly connected under each lower rib, the blades intersect at the central axis and a through hole is opened at the central axis for being mounted on the base.

[0011] Furthermore, the pitch angle of each blade of the upper fan blade is 0°, and the projected area angle is 95°; the pitch angle of each blade of the lower fan blade is 0°, and the projected area angle is 60°.

[0012] Furthermore, the power management circuit includes: a rectifier and filter unit, an energy storage unit, an overvoltage protection unit, and a voltage stabilization unit;

[0013] 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;

[0014] The energy storage unit is used to store the direct current converted by the rectification and filtering unit;

[0015] The overvoltage protection unit is used to protect the circuit and release the voltage when the voltage exceeds the set threshold;

[0016] The voltage stabilizing unit is used to ensure that the output voltage of the power management circuit is always close to the set value.

[0017] The beneficial effects of the present invention are:

[0018] (1) The system of the present invention is self-powered, so it can continuously monitor the strain changes of the bridge, protect and warn the bridge safety based on the collected data, effectively delay the aging of the bridge structure, reduce its wear and tear, thereby extending the service life of the bridge and reducing the need for frequent reconstruction or large-scale maintenance.

[0019] (2) The wind energy conversion device designed in the present invention greatly increases the power generation and improves the power generation efficiency through electromagnetic power generation and two types of friction nano power generation, as well as electromagnetic power generation; and the nested design greatly increases the space utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural block diagram of a bridge self-powered strain sensing system based on friction nano-power generation and electromagnetic power generation in an embodiment of the present invention.

[0021] Figure 2 It is a schematic structural diagram of a wind energy conversion device in an embodiment of the present invention.

[0022] Figure 3It is a schematic diagram of the upper cylinder structure of the wind energy conversion device in an embodiment of the present invention.

[0023] Figure 4 It is a schematic diagram of the lower barrel structure of the wind energy conversion device in an embodiment of the present invention.

[0024] Figure 5 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.

[0025] Figure 6 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.

[0026] In the figure, upper cylinder 1, upper cylinder 1-1, upper inclined rail 1-2, upper rib 1-3, upper blade 1-4, grid copper electrode 1-5, gap one 1-6, polyester fiber wool 1-7, coil 1-8; lower cylinder 2, lower cylinder 2-1, lower inclined rail 2-2, lower rib 2-3, lower blade 2-4, nylon membrane 2-5, PTFE (polytetrafluoroethylene) membrane 2-6, gap two 2-7, permanent magnet 2-8; base 3, support rod 3-1, truncated table 3-2; ball 4. DETAILED DESCRIPTION

[0027] 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.

[0028] like Figure 1 As shown, a bridge self-powered strain sensing system based on friction nano-generation and electromagnetic generation includes: a wind energy conversion device, a power management circuit, a sensing unit, and a micro-control unit. The wind energy conversion device collects clean energy based on electromagnetic generators and friction nano-generators, 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 sensing unit and the micro-control unit; the sensing unit is a strain sensor, which displays the strain of the key nodes of the bridge and represents the health of the bridge. The micro-control unit is used to transmit the monitoring data of the sensing unit, and finally realize the self-power supply of the strain sensing system. The power management circuit includes: a rectifier and filter unit, an energy storage unit, an overvoltage protection unit, and a voltage stabilization unit.

[0029] The rectifier and filter unit includes a rectifier circuit and a filter. The rectifier circuit converts alternating current (AC) into direct current (DC). During the rectification process, although the direction of the current has been converted to unidirectional, its form is usually a pulse waveform rather than a completely smooth DC signal. The role of the filter is to smooth these pulses and reduce the ripple in the current, thereby producing an output that is closer to the ideal DC.

[0030] The energy storage unit stores electrical energy through a combined circuit of capacitor C and inductor L. The capacitor stores energy by establishing an electric field between two conductor plates; the inductor stores energy by establishing a magnetic field in its coil.

[0031] Overvoltage protection unit: Since the voltage generated by TENG is too large, and the voltage generated by EMG also fluctuates with the rotation speed (wind speed), the voltage is not a stable value; the overvoltage protection unit is used to protect subsequent devices and release the pressure when the voltage exceeds the threshold.

[0032] The voltage regulator ensures that the output voltage is always close to a set value regardless of changes in input voltage or load conditions.

[0033] like Figure 2 As shown, the wind energy conversion device includes: an electromagnetic generator (EMG) unit and a triboelectric nanogenerator (TENG) unit, and the structure includes: an upper cylinder 1, a lower cylinder 2, a base 3, and a ball 4. The base 3 includes a support rod 3-1 and a truncated cone 3-2, and the support rod 3-1 is fixedly connected to the center of the upper surface of the truncated cone 3-2; in this embodiment, the height of the truncated cone 3-2 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 3-1 is 1 cm and the height is 50 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 3-1. The surface material of the ball 4 is FEP (Fluorinated Ethylene Propylene).

[0034] like Figure 3As shown, the upper cylinder 1 includes: an upper cylinder 1-1, an upper inclined rail 1-2, an upper rib 1-3, an upper fan blade 1-4, a grid-shaped copper electrode 1-5, a gap 1-6, a polyester fiber wool 1-7, and a coil 1-8. The upper cylinder 1-1 is a tubular structure, and a plurality of upper ribs 1-3 are arranged on its upper surface. One end of each upper rib 1-3 is fixedly connected to the cylinder wall of the upper cylinder 1-1, and the other end is fixedly connected to the central axis. A through hole is provided at the central axis for sleeve installation on the support rod 3-1. Upper fan blades 1-4 are evenly arranged circumferentially on the outer wall of the upper cylinder 1-1, and the upper fan blades 1-4 include a plurality of blades twisted in the same direction. A plurality of upper inclined rails 1-2 are respectively provided on the outer wall surface of the upper cylinder 1-1 and on the upward side of the upper fan blade 1-4, and a grid-shaped copper electrode 1-5 is laid in the upper inclined rail 1-2 to accommodate the ball 4 sliding or rolling in the upper inclined rail 1-2. A flexible PCB, i.e., a grid copper electrode 1-5, is attached to the inner wall of the upper cylinder 1-1. The grid copper electrode 1-5 is evenly provided with multiple gaps 1-6 in the circumferential direction. Each gap 1-6 is arranged, and polyester fiber wool 1-7 is arranged in the gap 1-6 to increase friction. Multiple coil slots are evenly arranged in the circumferential direction of the inner wall of the upper cylinder 1-1. A coil 1-8 is installed in each coil slot. The coil slot is used to position and protect the coil 1-8. The coils 1-8 are placed in the same direction (clockwise or counterclockwise) and divided into two groups according to the position interval (taking the circumferential arrangement of 6 coils 1-6 as an example, they are divided into two groups A and B. The coils 1-6 are arranged in the circumferential order of: A, B, A, B, A, B). When connected, the coils 1-8 in the group are connected in series, and then after passing through the rectifier bridge, the two windings are connected in parallel.

[0035] In this embodiment, there are three upper ribs 1-3, one ends of the three upper ribs 1-3 intersect and the intersection is located on the central axis of the upper cylinder 1-1, and the other ends are fixedly connected to the outer periphery of the upper surface of the upper cylinder 1-1, and the angle between adjacent upper ribs 1-3 is 120°; the upper fan blades 1-4 have a total of five blades, each blade is 9.5 cm long, 20 cm high, has a pitch angle of 0°, a projection area angle of 95°, and a blade thickness of 0.1 cm. The inner diameter of the upper cylinder 1-1 is 21 cm, the outer diameter is 25 cm (i.e., the wall thickness is 2 cm), and the height is 20 cm; the grid-shaped copper electrode 1-5 attached to the inner wall of the upper cylinder 1-1 has four pairs of poles, one pole is (2.625π-0.5) cm wide and 16 cm long, and the grid-shaped copper electrode 1-5 is evenly provided with eight gaps 1-6 with a width of 0.5 cm in the circumferential direction, wherein the four gaps 1-6 are provided with polyester fiber wool 1-7 with a width of 0.5 cm; 20 coil slots are evenly provided on the inner wall of the upper cylinder 1-1 in the circumferential direction, wherein the 20 installed coils 1-8 are all 2.3 cm long, 0.4 cm wide, 15 cm high, and have a wire diameter of 0.1 mm.

[0036] like Figure 4As shown, the lower cylinder 2 includes: a lower cylinder 2-1, a lower inclined rail 2-2, a lower rib 2-3, a lower blade 2-4, a nylon membrane 2-5, a PTFE membrane 2-6, a gap 2-7, and a permanent magnet 2-8. The lower cylinder 2-1 is also a tubular structure, and its outer diameter is slightly smaller than the inner diameter of the upper cylinder 1-1, and its height is the same as that of the upper cylinder 1-1. The upper cylinder 1-1 is sleeved on the outer circumference of the lower cylinder 2-1; the lower surface of the lower cylinder 2-1 is fixedly connected to the lower blade 2-4 through a plurality of lower ribs 2-3, and the lower blade 2-4 includes a plurality of blades, and the torsion direction of the blade is opposite to that of the upper blade 1-4; a blade of the lower blade 2-4 is fixedly connected below each lower rib 2-3, and the blades intersect at the central axis and a through hole is provided at the central axis for sleeve installation on the support rod 3-1. A plurality of lower inclined rails 2-2 are respectively provided on the inner wall surface of the lower cylinder 2-1 and the lower blades 2-4. A grid-shaped copper electrode 1-5 is laid inside the lower inclined rail 2-2 to accommodate the sliding or rolling of the ball 4 in the upper inclined rail 1-2. Multiple pieces of nylon membranes 2-5 and PTFE membranes 2-6 of the same number are evenly attached circumferentially on the outer wall of the lower cylinder 2-1. The two membranes are staggered and attached at intervals, and a gap 2-7 is left between two adjacent membranes. A plurality of permanent magnet slots are evenly provided circumferentially on the inner wall of the lower cylinder 2-1. A permanent magnet 2-8 is installed in each permanent magnet slot. The permanent magnet slot is used to locate, fix and protect the permanent magnet 2-8. The permanent magnets 2-8 are staggered in sequence according to the position in the order of NS. The ratio of the number of permanent magnets 2-8 to the number of coils 1-8 is 1:1.

[0037] In this embodiment, there are three lower ribs 2-3, one ends of the three lower ribs 2-3 intersect and the intersection is located on the central axis of the lower cylinder 2-1, and the other ends are fixedly connected to the outer periphery of the upper surface of the lower cylinder 2-1, and the angle between adjacent lower ribs 2-3 is 120°; the lower fan blade 2-4 has three blades, each blade is 8.5 cm long, 20 cm high, has a pitch angle of 0°, a projection area angle of 60°, and a blade thickness of 0.05 cm. The inner diameter of the lower cylinder 2-1 is 16 cm, the outer diameter is 20 cm (i.e., the wall thickness is 2 cm), and the height is 20 cm; the width of each nylon membrane 2-5 and PTFE membrane 2-6 is (2.5π-0.5) cm, the length is 16 cm, and the width of the gap 2-7 is 0.5 cm; 20 permanent magnet grooves are evenly arranged on the inner circumference of the wall of the lower cylinder 2-1, among which the 20 permanent magnets 2-8 installed are 1.8 cm long, 0.4 cm wide, and 15 cm high.

[0038] When the wind energy conversion device is working, when the wind caused by natural wind or the disturbance of airflow after the vehicle passes by blows toward the wind energy conversion device, due to the action of wind force, the upper blades 1-4 of the upper cylinder 1 and the lower blades 2-4 of the lower cylinder 2 rotate in the opposite direction, thereby driving the upper cylinder 1-1 and the lower cylinder 2-1 fixed thereto to rotate in the opposite direction. Taking the upper cylinder 1 rotating counterclockwise and the lower cylinder 2 rotating clockwise as an example, the upper cylinder 1 drives the coil 1-8, the grid copper electrode 1-5 and the polyester fiber wool 1-7 to rotate counterclockwise, and the lower cylinder 2 drives the permanent magnet 2-8, the PTFE membrane 2-6 and the nylon membrane 2-5 to move clockwise. Since the rotation directions are opposite, it is equivalent to doubling the rotation speed of the entire device under the same wind speed, and the power generation efficiency is improved.

[0039] The relative rotation between the coil 1-8 and the permanent magnet 2-8 can realize EMG power generation. The principle is as follows: the permanent magnet 2-8 with staggered polarity rotates to generate an alternating magnetic field. According to Lenz's law, the induced current generated in the coil 1-8 always resists the change of magnetic flux. When the magnet is close to the coil 1-8, the coil 1-8 generates an induced current in one direction to resist the increase of magnetic flux density. When the magnet is away from the coil 1-8, the coil 1-8 generates an induced current in the opposite direction to resist the decrease of magnetic flux density. Due to the staggered polarity of the permanent magnet 2-8, the coil 1-8 with alternating poles is staggered into two groups, and the current direction of each group is opposite. When the permanent magnet 2-8 rotates continuously, the coil 1-8 generates continuous alternating current.

[0040] The relative rotation of the above-mentioned grid-shaped copper electrode 1-5, polyester fiber wool 1-7, PTFE membrane 2-6, and nylon membrane 2-5 can realize the first type of TENG power generation, and the principle is as follows: Figure 5 As shown, the three materials, nylon membrane 2-5, PTFE membrane 2-6 and polyester fiber hair 1-7, have different abilities to gain or lose electrons. Among them, PTFE membrane 2-6 is most likely to gain electrons and show electronegativity, nylon membrane 2-5 is most likely to lose electrons and show electronegativity, and the ability of polyester fiber hair 1-7 to gain or lose electrons is between the two. Therefore, when nylon membrane 2-5 and PTFE membrane 2-6 are rubbed with polyester fiber hair 1-7 together, polyester fiber hair 1-7 increases charge transfer, so that PTFE membrane 2-6 and nylon membrane 2-5 both carry equal and opposite charges, and gradually tend to saturation during friction. The charges on PTFE membrane 2-6 and nylon membrane 2-5 will not disappear or transfer in a short time. At this time, the electrons of the grid copper electrode 1-5 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 1-7 to indirectly rub the positive and negative friction layers (nylon membrane 2-5 and PTFE membrane 2-6), thereby increasing space utilization and potential difference, thereby increasing electron transfer. In addition, the use of polyester fiber hair 1-7 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.

[0041] When the upper cylinder 1 and the lower cylinder 2 rotate in opposite directions, the ball 4 with the FEP surface slides on the upper inclined rail 1-2 and the lower inclined rail 2-2 with the grid-shaped copper electrodes 1-5 due to inertia, so that irregular alternating current can be derived from the rails.

[0042] The ball 4 moves relative to the track on which the grid-shaped copper electrodes 1-5 are laid, and the second type of TENG power generation can be realized. The principle is as follows: Figure 6 As shown, the grid copper electrode 1-5 is laid on the upper inclined rail 1-2 and the lower inclined rail 2-2. At this time, the grid copper electrode 1-5 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 1-5 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 1-5 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.

[0043] 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 stabilization unit. During this process, the overvoltage protection unit always protects the circuit to ensure the normal operation of the strain sensing system.

[0044] The present invention proposes a bridge self-powered strain sensing system based on friction nano-power generation and electromagnetic power generation. This system does not rely on external power sources, but can generate the required electricity by itself, significantly improving the credibility and continuity of bridge structure health monitoring. The present invention cleverly utilizes the energy in the natural environment where the bridge is located, especially the wind energy generated by natural wind and the disturbance of air flow caused by the passing of vehicles; the wind energy conversion device in the system can effectively capture this wind energy and convert it into electrical energy to supply the strain sensor.

[0045] 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 strain sensing system based on friction nano-generation and electromagnetic generation, characterized in that: include: Wind energy conversion device, power management circuit, sensor unit, micro-control unit; The wind energy conversion device converts wind energy into electrical energy, which is then converted into DC voltage through a power management circuit to power a sensing unit and a micro-control unit. The sensing unit is a strain sensor, and the micro-control unit is used to transmit data of the sensing unit. The wind energy conversion device 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 the central axis, and the upper cylinder is sleeved on the outer periphery of the lower cylinder; the surface of the ball is made of FEP; The upper cylinder comprises: an upper cylinder, an upper inclined rail, an upper rib, an upper fan blade, a grid-shaped copper electrode, a gap one, polyester fiber wool, and a coil; the upper cylinder is a tubular structure, which is fixedly connected to the central axis through the upper rib, and the central axis is sleeved on the base; the upper fan blade is fixedly connected to the outer wall of the upper cylinder evenly in the circumferential direction, and the upper fan blade comprises a plurality of blades twisted in the same direction; a plurality of upper inclined rails are respectively provided on the outer wall of the upper cylinder and the outer surface of the upper fan blade, and a grid-shaped copper electrode is laid in the upper inclined rail, and the ball slides or rolls in the upper inclined rail; the grid-shaped copper electrode is attached to the inner wall of the upper cylinder, and a plurality of gaps one are evenly provided in the circumferential direction of the grid-shaped copper electrode, and each gap one is arranged, and polyester fiber wool is arranged in the gap one; a plurality of coil slots are evenly provided in the circumferential direction of the inner wall of the upper cylinder, and a coil is installed in each coil slot, and the coils are divided into two groups according to the position interval, and the coils in the group are connected in series when connected, and the two groups of coils are connected in parallel after passing through the rectifier bridge; The lower cylinder comprises: a lower cylinder, a lower inclined rail, a lower rib, a lower blade, a nylon membrane, a PTFE membrane, a gap 2, and a permanent magnet; the lower cylinder is a tubular structure, and its outer diameter is smaller than the inner diameter of the upper cylinder, and the upper cylinder is sleeved on the outer circumference of the lower cylinder; the lower surface of the lower cylinder is fixedly connected to the lower blade through the lower rib, and the torsion direction of the lower blade is opposite to that of the upper blade; a plurality of lower inclined rails are respectively provided on the upper and lower blades of the inner wall of the lower cylinder, and a grid-shaped copper electrode is laid in the lower inclined rail, and the ball slides or rolls in the lower inclined rail; a plurality of pieces of nylon membrane and PTFE membrane of the same number are evenly attached circumferentially on the outer wall of the lower cylinder, and the nylon membrane and the PTFE membrane are attached alternately at intervals; the inner wall of the lower cylinder is evenly provided with permanent magnet slots of the same number as the coil slots, and a permanent magnet is installed in each permanent magnet slot, and the permanent magnets are arranged in an NS staggered manner.

2. The bridge self-powered strain sensing system based on friction nano-power generation and electromagnetic power generation according to claim 1 is characterized in that: There are three upper ribs, one end of the three upper ribs intersects and the intersection is located at the central axis of the upper cylinder, and the other end is fixedly connected to the outer periphery of the upper surface of the upper cylinder, and the angle between adjacent upper ribs is 120°; the upper fan blade includes three blades, and a blade of the upper fan blade is fixedly connected above each upper rib, and the blades intersect at the central axis and a through hole is provided at the central axis for sleeve installation on the base; There are three lower ribs, one end of the three lower ribs intersect and the intersection is located at the central axis of the lower cylinder, the other end is fixedly connected to the outer periphery of the lower surface of the lower cylinder, and the angle between adjacent lower ribs is 120°; the lower fan blade includes three blades, a blade of the lower fan blade is fixedly connected under each lower rib, the blades intersect at the central axis and a through hole is opened at the central axis for being mounted on the base.

3. The bridge self-powered strain sensing system based on friction nano-power generation and electromagnetic power generation according to claim 1 is characterized in that: The pitch angle of each blade of the upper fan blade is 0°, and the projected area angle is 95°; the pitch angle of each blade of the lower fan blade is 0°, and the projected area angle is 60°.

4. The bridge self-powered strain sensing system based on friction nano-power generation and electromagnetic power generation according to claim 1 is characterized in that: The power management circuit includes: a rectifier and filter unit, 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.

Images