Bridge cable force self-powered monitoring system based on triboelectric nanogeneration and electromagnetic generation

Abstract

The present invention discloses a self-powered monitoring system for bridge cable tension based on triboelectric nano-generation and electromagnetic generation. A hybrid energy harvester converts wind energy into electrical energy, which is then converted to DC voltage through a power management circuit to power the remaining units. The hybrid energy harvester comprises a ball bearing with a FEP surface, a coaxially mounted rotatable upper and lower cylinders, the cylinders and blades of which are fixedly connected by ribs, and the upper and lower blades twist in opposite directions. Multiple inclined rails are provided on the outer wall of the upper cylinder, the inner wall of the lower cylinder, and the upper and lower blades to accommodate the ball bearings. Grid-shaped copper electrodes are attached to the inner wall of the upper cylinder at intervals, with polyester fiber fibers arranged in between. Multiple coils are embedded in the circumference of the upper cylinder, and multiple permanent magnets are embedded in the corresponding circumference of the lower cylinder. Multiple nylon and PTFE membranes are evenly and staggeredly attached to the outer wall of the lower cylinder. The present invention achieves self-powered monitoring, ensuring continuous and real-time monitoring of bridge cable tension.

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 cable force self-powered monitoring system based on friction nano-power generation and electromagnetic power generation. Background Art

[0002] Bridges are crucial nodes in transportation networks, connecting different regions and facilitating the flow of people and goods. The strength and safety of these structures directly impact the safety of life and property, as well as the smooth flow of economic and social activities. Over time, bridges may gradually show signs of structural damage and fatigue due to continued use, corrosion from environmental factors, and excessive loads. Furthermore, increasing traffic volumes and potential overloads further increase the likelihood of structural failure. Therefore, continuous monitoring and health assessment of bridges are crucial.

[0003] Accelerometers play a crucial role in bridge health monitoring systems. They are high-precision sensing devices that measure and monitor the acceleration of bridge cable structures, reflecting their vibration and cable tension states. Real-time or periodic acceleration data allows engineers to analyze the structural performance and stability of bridge cables and promptly identify potential structural problems. Such monitoring not only helps maintain bridge safety and extend their service life, but also enables the effective planning of repair and reinforcement work, thereby reducing maintenance costs. Furthermore, the data provided by accelerometers is invaluable for validating bridge design assumptions, improving future bridge designs, and developing more effective bridge maintenance strategies. Therefore, accelerometers are an indispensable component of bridge cable health monitoring systems and are crucial for ensuring public safety and improving infrastructure efficiency. However, the accelerometers currently in widespread use rely on chemical batteries for power, which makes maintenance and replacement difficult, potentially leading to temporary failure of the monitoring system during maintenance and replacement. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention proposes a bridge cable force self-powered monitoring system based on friction nano-power generation and electromagnetic power generation.

[0005] The specific technical solutions are as follows:

[0006] A self-powered bridge cable force monitoring system based on triboelectric nano-generation and electromagnetic power generation includes a hybrid energy harvester, a power management circuit, a sensor unit, and a micro-control unit. The hybrid energy harvester converts wind energy into electrical energy, which is then converted into DC voltage by the power management circuit to power the sensor unit and the micro-control unit. The micro-control unit is used to transmit data from the sensor unit. The hybrid energy harvester includes an upper cylinder, a lower cylinder, a base, and a ball bearing. The upper and lower cylinders are coaxially sleeved on the base and can rotate around a central axis. The surface material of the ball bearing is FEP.

[0007] The upper cylinder comprises: an upper cylinder, an upper inclined rail, an upper fan blade, an upper rib, a coil, a grid-shaped copper electrode, a gap 1, and polyester fiber wool; the upper cylinder is a tubular structure, and its upper surface is fixedly connected to the upper fan blade via an upper rib; a plurality of upper inclined rails are respectively provided on the outer circumference of the upper cylinder and on the upper fan blade, and a grid-shaped copper electrode is laid in the upper inclined rail to accommodate the sliding or rolling of the ball; the grid-shaped copper electrode is attached to the inner wall of the upper cylinder, and a plurality of gaps 1 are evenly provided on the grid copper electrode in the circumferential direction, and polyester fiber wool is arranged in each gap 1; a plurality of coil slots are evenly provided on the inner wall of the upper cylinder in the circumferential direction, and a coil is installed in each coil slot. The coils are divided into two groups according to the position interval. When connected, the coils in the group are connected in series, and after passing through the rectifier bridge, the two groups of coils are connected in parallel;

[0008] The lower cylinder includes: a lower cylinder, a lower inclined rail, a lower fan blade, a lower rib, a permanent magnet, a nylon membrane, a PTFE membrane, and a gap two; the lower cylinder is a tubular structure, the outer diameter of which is smaller than the inner diameter of the upper cylinder, and the upper cylinder is coaxially sleeved on the outer circumference of the lower cylinder; the lower surface of the lower cylinder is fixedly connected to the lower fan blade through the lower rib, and the torsion direction of the lower fan blade is opposite to that of the upper fan blade; a plurality of lower inclined rails are respectively provided on the inner circumference of the lower cylinder and the lower fan blade, and a grid-shaped copper electrode is laid in the lower inclined rail to accommodate the sliding or rolling of the ball; 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 PTFE membrane are attached at intervals and staggered; a plurality of permanent magnet slots are circumferentially provided on the inner wall of the lower cylinder, and a permanent magnet is installed in each permanent magnet slot, and the permanent magnets are staggered in NS arrangement, and the ratio of the number of permanent magnets to coils is 1:1.

[0009] Furthermore, the balls are selected from any one of fan-blade spherical balls, fan-blade cylindrical balls, wing-shaped spherical balls, and wing-shaped cylindrical balls;

[0010] The fan-shaped spherical ball bearing comprises a fan blade, a support member, and a spherical ball bearing; a mounting rod of the support member passes through the spherical ball bearing along a diameter, and the spherical ball bearing can rotate with the mounting rod as a rotation axis; the fan blade is fixedly connected to another mounting rod of the support member, and the two mounting rods are parallel and opposite to each other;

[0011] The fan-blade cylindrical ball bearing comprises a fan blade, a support member, and a cylindrical ball bearing; a mounting rod of the support member passes through the central axis of the cylindrical ball bearing, and the cylindrical ball bearing can rotate with the mounting rod as a rotation axis; the fan blade is fixedly connected to another mounting rod of the support member;

[0012] The wing-shaped spherical ball includes a wing, a support member, and a spherical ball; a mounting rod of the support member passes through the spherical ball along a diameter, and the spherical ball can rotate with the mounting rod as a rotation axis; the wing is fixedly connected to another mounting rod of the support member;

[0013] The wing-shaped cylindrical ball includes a wing, a support member, and a cylindrical ball; a mounting rod of the support member passes through the central axis of the cylindrical ball, and the cylindrical ball can rotate with the mounting rod as the rotation axis; the wing is fixedly connected to another mounting rod of the support member.

[0014] 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 have a through hole at the central axis for being sleeved on the base;

[0015] There are three lower ribs, one end of the three lower ribs intersects and the intersection is located at the central axis of the lower cylinder, and 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, and 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.

[0016] Furthermore, the pitch angle of each blade of the upper fan blade and the lower fan blade is 0°, and the projected area angle is 60°.

[0017] Furthermore, the power management circuit includes: a rectifier and filter unit, 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. The rectification circuit is used to convert alternating current into direct current; the filter is used to reduce ripples in the current and generate an output closer to 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 present invention provides a continuous monitoring system for bridge structures that does not require an external power source. It utilizes the environmental resources of the bridge itself to power the monitoring equipment, overcomes the problem of monitoring interruption during chemical battery replacement and maintenance, and ensures continuous real-time monitoring of the bridge cables.

[0024] (2) The hybrid energy harvester 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; and the nested design greatly increases the space utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural block diagram of a bridge cable force self-powered monitoring system based on friction nano-power generation and electromagnetic power generation proposed in an embodiment of the present invention.

[0026] Figure 2 Schematic diagram of the structure of the hybrid energy harvester in an embodiment of the present invention.

[0027] Figure 3 Schematic diagram of the upper cylinder structure of the hybrid energy collector in an embodiment of the present invention, wherein (a) is a main view and (b) is a three-dimensional schematic diagram from a top view.

[0028] Figure 4 Schematic diagram of the lower tube structure of the hybrid energy collector in an embodiment of the present invention, wherein (a) is a main view and (b) is a three-dimensional schematic diagram from a top view.

[0029] Figure 5 Schematic diagram of the base structure of the hybrid energy collector in an embodiment of the present invention.

[0030] Figure 6 Schematic diagrams of different types of balls in the hybrid energy collector in an embodiment of the present invention, wherein (a) is a schematic diagram of a fan-blade type spherical ball, (b) is a schematic diagram of a wing type spherical ball, (c) is a schematic diagram of a fan-blade type cylindrical ball, and (d) is a schematic diagram of a wing type cylindrical ball.

[0031] Figure 7 This 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 8 This 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] In the figure, upper cylinder 1, upper cylinder 1-1, upper inclined rail 1-2, upper blade 1-3, upper rib 1-4, coil 1-5, grid-shaped copper electrode 1-6, gap one 1-7, polyester fiber wool 1-8; lower cylinder 2, lower cylinder 2-1, lower inclined rail 2-2, lower blade 2-3, lower rib 2-4, permanent magnet 2-5, nylon film 2-6, PTFE (polytetrafluoroethylene) film 2-7, gap two 2-8; base 3, frustum 3-1, center support rod 3-2; ball 4, blade-shaped spherical ball 4-1, wing-shaped spherical ball 4-2, blade-shaped cylindrical ball 4-3, wing-shaped cylindrical ball 4-4. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments. The purpose and effects of the present invention will become more apparent. 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 for explaining the present invention and are not intended to limit the present invention.

[0035] like Figure 1 A self-powered bridge cable force monitoring system based on triboelectric nanogenerators and electromagnetic power generation is shown. The system comprises a hybrid energy harvester, a power management circuit, a sensor unit, and a microcontroller. The hybrid energy harvester utilizes electromagnetic generators and triboelectric nanogenerators to harvest clean energy, specifically wind energy from the bridge. This energy is converted into electrical energy through the power management circuit, which then outputs a DC voltage to power the sensor unit and microcontroller. The microcontroller then transmits data monitored by the sensor unit, ultimately achieving self-powered monitoring. The power management circuit includes a rectifier and filter unit, an energy storage unit, an overvoltage protection unit, and a voltage regulator.

[0036] 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 closer to ideal DC.

[0037] 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.

[0038] Overvoltage protection unit: Since the voltage generated by the TENG is too large, and the voltage generated by the 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.

[0039] The voltage stabilization unit ensures that the output voltage remains close to a set value regardless of changes in input voltage or load conditions.

[0040] The sensing unit in the present invention is mainly an acceleration sensor, which displays the acceleration of the key nodes of the bridge cable and represents the health status of the bridge cable.

[0041] like Figure 2 As shown, the hybrid energy harvester includes an electromagnetic generator (EMG) unit and a triboelectric nanogenerator (TENG) unit. Its structure comprises an upper tube 1, a lower tube 2, a base 3, and a ball 4. The upper tube 1 and the lower tube 2 are coaxially mounted on the base 3, with the upper tube 1 mounted on the outer periphery of the lower tube 2. Both the upper tube 1 and the lower tube 2 can rotate around the central support rod 3-2.

[0042] like Figure 3 As shown, the upper cylinder 1 comprises: an upper cylinder 1-1, an upper inclined rail 1-2, upper blades 1-3, upper ribs 1-4, a coil 1-5, a grid-shaped copper electrode 1-6, a gap 1-7, and polyester fiber hair 1-8. The upper cylinder 1-1 is a tubular structure, its upper surface being fixedly connected to the upper blades 1-3 via three upper ribs 1-4. The three upper ribs 1-4 intersect at one end, with their intersection located at the central axis of the upper cylinder 1-1, and their other ends fixedly connected to the outer periphery of the upper surface of the upper cylinder 1-1. The angle between adjacent upper ribs 1-4 is 120°. A blade of the upper blade 1-3 is fixedly connected to each upper rib 1-4, for a total of three blades. The blades intersect at the central axis and have a through-hole at the central axis for sleeve mounting on the base 3. Multiple upper inclined rails 1-2 are defined on the outer circumference of the upper cylinder 1-1 and on the upward-facing side of the upper blades 1-3. Grid-shaped copper electrodes 1-6 are placed within these rails to accommodate the sliding or rolling motion of the balls 4. A flexible PCB, or grid-shaped copper electrodes 1-6, is attached to the inner wall of the upper cylinder 1-1. Multiple gaps 1-7 are evenly spaced around the grid-shaped copper electrodes 1-6. Each gap 1-7 is separated by polyester fiber fleeces 1-8 to increase friction and saturate the charge on the nylon membrane 2-6 and PTFE membrane 2-7. Internal coil slots are uniformly arranged circumferentially within the upper cylinder 1-1, with a coil 1-5 installed in each slot. The coil slots are used to position and protect the coils 1-5. The coils 1-5 are placed sequentially in the same direction (clockwise or counterclockwise) and divided into two groups based on their spacing (taking the example of six coils 1-6 uniformly arranged circumferentially, they are divided into two groups A and B, with the coils 1-6 arranged circumferentially in the following order: A, B, A, B, A, B). When connected, the coils 1-5 within a group are connected in series, and then after passing through a rectifier bridge, the two windings are connected in parallel. The grid-like copper electrodes 1-6 are also spaced apart and divided into two groups, which can be regarded as the two poles of the AC output terminal.

[0043] In this embodiment, the upper cylinder 1-1 has an inner diameter of 21 cm, an outer diameter of 25 cm (i.e., a wall thickness of 2 cm), and a height of 20 cm. Attached to the inner wall of the upper cylinder 1-1 are four pairs of grid-shaped copper electrodes 1-6, each with a width of (2.625π - 0.5) cm and a length of 16 cm. The grid-shaped copper electrodes 1-6 are uniformly spaced around the circumference, with eight 0.5 cm wide gaps 1-7 interspersed with four 0.5 cm wide polyester fiber strands 1-8. Twenty slots are uniformly spaced around the inner circumference of the upper cylinder 1-1, housing twenty coils 1-5, each measuring 2.3 cm long, 0.4 cm wide, and 15 cm high, with a wire diameter of 0.1 mm. The upper fan blades 1-3 are 9.5 cm long, 20 cm high, with a pitch angle of 0°, a projected area angle of 60°, and a thickness of 0.05 cm.

[0044] like Figure 4 As shown, the lower cylinder 2 includes: a lower cylinder 2-1, a lower inclined rail 2-2, a lower fan blade 2-3, a lower rib 2-4, a permanent magnet 2-5, a nylon membrane 2-6, a PTFE membrane 2-7, and a gap 2-8. The lower cylinder 2-1 is also a tubular structure, with an outer diameter slightly smaller than the inner diameter of the upper cylinder 1-1 and the same height as the upper cylinder 1-1; the lower surface of the lower cylinder 2-1 is fixedly connected to the lower fan blade 2-3 through three lower ribs 2-4, one end of the three lower ribs 2-4 intersects and the intersection is located on the central axis of the lower cylinder 2-1, and the other end is fixedly connected to the outer periphery of the upper surface of the lower cylinder 2-1, and the angle between adjacent lower ribs 2-4 is 120°; a blade of the lower fan blade 2-3 is fixedly connected under each lower rib 2-4, for a total of three blades, which intersect at the central axis and have a through hole at the central axis for being mounted on the base 3; the torsion direction of the lower fan blade 2-3 is opposite to that of the upper fan blade 1-3. Multiple lower inclined rails 2-2 are provided on the inner circumference of the lower cylinder 2-1 and on the upward-facing side of the lower blades 2-3. Grid-shaped copper electrodes 1-6 are laid within the lower inclined rails 2-2 to accommodate the sliding or rolling motion of the balls 4 within them. Multiple, equal numbers of nylon membranes 2-6 and PTFE membranes 2-7 are evenly and circumferentially affixed to the outer wall of the lower cylinder 2-1. The two membranes are staggered, with gaps 2-8 between adjacent membranes. Twenty permanent magnet slots are evenly and circumferentially defined within the lower cylinder 2-1, each housing a permanent magnet 2-5. The slots serve to position and protect the permanent magnets 2-5. The permanent magnets 2-5 are arranged in a staggered arrangement (NS), with a 1:1 ratio of permanent magnets 2-5 to coils 1-5.

[0045] In this embodiment, 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 2-6 and PTFE membrane 2-7 is (2.5π-0.5) cm, the length is 16 cm, and the width of the gap 2-8 is 0.5 cm; 20 embedded permanent magnet slots are evenly arranged around the lower cylinder 2-1, in which 20 permanent magnets 2-5 are installed, and the permanent magnets 2-5 are 1.8 cm long, 0.4 cm wide, and 15 cm high; the blade length of the lower fan blade 2-3 is 8.5 cm, the height is 20 cm, the pitch angle is 0°, the projected area angle is 60°, and the blade thickness is 0.05 cm.

[0046] The EMG unit is a two-phase electromagnetic generator consisting of coils 1-5 and permanent magnets 2-5. The function of the first type of TENG unit is realized by the combination of grid copper electrodes 1-6, polyester fiber wool 1-8, nylon membranes 2-6, and PTFE membranes 2-7. The function of the second type of TENG unit is realized by the grid copper electrodes 1-6 and the ball 4 whose surface friction material is FEP (Fluorinated Ethylene Propylene).

[0047] like Figure 5 As shown, base 3 includes a truncated cone 3-1 and a central support rod 3-2, which is fixedly connected to the center of the upper surface of truncated cone 3-1. In this embodiment, truncated cone 3-1 has a height of 5 cm, an upper base diameter of 4 cm, and a lower base diameter of 32 cm; central support rod 3-2 has a diameter of 1 cm and a height of 70 cm.

[0048] like Figure 6 As shown, the ball 4 can be selected from: fan-blade type balls or wing-type balls. Due to the change in its structure, the fan-blade type ball is not limited to inertia as the excitation method. In a windy environment, it can also give the ball an upward force, overcoming gravity, increasing the ball's movement range and increasing friction. Due to the change in its structure, the wing-type ball is not limited to inertial drive as the excitation method. In a windy environment, the wing will rise, increasing the ball's movement range and thus increasing friction. The fan-blade type ball can be further divided into fan-blade type spherical balls 4-1 and fan-blade type cylindrical balls 4-3 according to the ball type. The wing-type ball can be divided into wing type spherical balls 4-2 and wing type cylindrical balls 4-4 according to the ball type. A single spherical ball can roll freely in the inclined rail, but because of its smooth surface and relatively flat structure, its most effective excitation method is inertial drive. A single cylindrical ball can also roll freely in the inclined rail, but its contact area with the inclined rail is increased from a point to a line compared to the spherical ball, increasing the friction area and friction. The structures of various types of balls 4 are as follows:

[0049] The fan-blade-shaped spherical ball bearing 4-1 consists of three parts: a fan blade, a rectangular support member, and a spherical ball bearing. The rectangular support member includes two parallel mounting rods and two parallel connecting rods, both of which are perpendicular to each other. One mounting rod of the rectangular support member passes through the spherical ball bearing along its diameter, and the spherical ball bearing can rotate about this mounting rod. The fan blade is fixed to the other mounting rod of the rectangular support member, and can drive the fan-blade-shaped spherical ball bearing 4-1 to roll or slide under the influence of wind. In this embodiment, the surface material of the spherical ball is FEP, and the fan blade has three blades; the diameter of the spherical ball embedded in the upper inclined rail 1-2 opened on the outer wall of the upper cylinder 1-1 and the lower inclined rail 2-2 opened on the inner wall of the lower cylinder 2-1 is 1 cm, and the swept diameter of the fan blade is 1 cm; the diameter of the spherical ball embedded in the upper inclined rail 1-2 opened on the upper fan blade 1-3 and the lower inclined rail 2-2 opened on the lower fan blade 2-3 is 0.5 cm, and the swept diameter of the fan blade is 0.5 cm; the size ratio of the ball located in the fan blade inclined rail and the ball located in the cylinder inclined rail is 1:2.

[0050] The fan-blade-shaped cylindrical ball 4-3 consists of three parts: a fan blade, a rectangular support, and a cylindrical ball; a mounting rod of the rectangular support passes through the cylindrical ball along the center axis, and the cylindrical ball can rotate with the mounting rod as the rotation axis; the fan blade is fixedly connected to another mounting rod of the rectangular support, and can drive the fan-blade-shaped cylindrical ball 4-3 to roll or slide under the action of wind. In this embodiment, the surface material of the cylindrical ball is FEP, and the fan blade has three blades; the bottom diameter of the cylindrical ball embedded in the upper inclined rail 1-2 opened on the outer wall of the upper cylinder 1-1 and the lower inclined rail 2-2 opened on the inner wall of the lower cylinder 2-1 is 1 cm, the height is 1 cm, and the swept diameter of the fan blade is 1 cm; the bottom diameter of the cylindrical ball embedded in the upper inclined rail 1-2 opened on the upper fan blade 1-3 and the lower inclined rail 2-2 opened on the lower fan blade 2-3 is 0.5 cm, the height is 0.5 cm; the swept diameter of the fan blade is 0.5 cm; the size ratio of the ball located in the fan blade inclined rail and the two balls located in the cylindrical inclined rail is 1:2.

[0051] The wing-shaped spherical ball bearing 4-2 consists of a wing, a rectangular support, and a spherical ball bearing. A mounting rod of the rectangular support passes through the spherical ball bearing along its diameter, and the spherical ball bearing can rotate about the mounting rod. The wing is fixed to another mounting rod of the rectangular support, and can drive the wing-shaped spherical ball bearing 4-2 to roll or slide under the action of wind. In this embodiment, the surface material of the spherical ball bearing is FEP. The spherical ball bearings embedded in the upper inclined track 1-2 on the outer wall of the upper cylinder 1-1 and the lower inclined track 2-2 on the inner wall of the lower cylinder 2-1 have a diameter of 1 cm and a wing length of 0.8 cm. The spherical ball bearings embedded in the upper inclined track 1-2 on the upper blade 1-3 and the lower inclined track 2-2 on the lower blade 2-3 have a diameter of 0.5 cm and a wing length of 0.4 cm. The size ratio of the balls located in the blade inclined track to the balls located in the cylinder inclined track is 1:2.

[0052] The wing-shaped cylindrical ball bearing 4-4 ​​is composed of three parts: a wing, a rectangular support member, and a cylindrical ball bearing; a mounting rod of the rectangular support member passes through the cylindrical ball bearing along the center axis, and the cylindrical ball bearing can rotate with the mounting rod as the rotation axis; the wing is fixedly connected to another mounting rod of the rectangular support member, and can drive the wing-shaped cylindrical ball bearing 4-4 ​​to roll or slide under the action of wind. In this embodiment, the surface material of the cylindrical ball is FEP; the bottom diameter of the cylindrical ball embedded in the upper inclined rail 1-2 opened on the outer wall of the upper cylinder 1-1 and the lower inclined rail 2-2 opened on the inner wall of the lower cylinder 2-1 is 1 cm, the height is 1 cm, and the wing length is 0.8 cm; the bottom diameter of the cylindrical ball embedded in the upper inclined rail 1-2 opened on the upper fan blade 1-3 and the lower inclined rail 2-2 opened on the lower fan blade 2-3 is 0.5 cm, the height is 0.5 cm, and the wing length is 0.4 cm; the size ratio of the ball located in the fan blade inclined rail and the two balls located in the cylindrical inclined rail is 1:2.

[0053] When the hybrid energy harvester is actually used in operation, when the wind caused by natural wind or the disturbance of the airflow after a vehicle passes by blows toward the hybrid energy harvester, due to the action of wind and the design of the opposite twisting directions of the upper fan blades 1-3 and the lower fan blades 2-3, the upper fan blades 1-3 and the lower fan blades 2-3 rotate in opposite directions, and then the upper cylinder 1-1 fixedly connected to the upper fan blades 1-3 and the lower cylinder 2-1 fixedly connected to the lower fan blades 2-3 also rotate in opposite directions. The upper cylinder 1-1 drives the coil 1-5 of the EMG unit and the grid copper electrode 1-6 and polyester fiber hair 1-8 of the first type of TENG unit to rotate counterclockwise, and the lower cylinder 2-1 drives the permanent magnet 2-5 of the EMG unit and the PTFE membrane 2-7 and nylon membrane 2-6 of the first type of TENG unit to rotate clockwise.

[0054] The above relative rotation can realize EMG power generation. The principle is as follows: the permanent magnets 2-5 with alternating polarity rotate to generate an alternating magnetic field. According to Lenz's law, the induced current generated in the coils 1-5 always resists the change of magnetic flux. When the magnets approach the coils 1-5, the coils 1-5 generate an induced current in one direction to resist the increase in magnetic flux density. When the magnets move away from the coils 1-5, the coils 1-5 generate an induced current in the opposite direction to resist the decrease in magnetic flux density. Due to the alternating polarity of the permanent magnets 2-5, the coils 1-5 with alternating poles are staggered into two groups, and the current in each group is opposite in direction. When the permanent magnets 2-5 continue to rotate, the coils 1-5 generate continuous alternating current.

[0055] The friction generated by the relative rotation can realize the first type of TENG power generation. The principle is as follows: Figure 7As shown, due to the different abilities of nylon membrane 2-6, PTFE membrane 2-7, and polyester fiber 1-8 to gain or lose electrons, PTFE membrane 2-7 is most likely to gain electrons, resulting in a negative electronegativity, while nylon membrane 2-6 is most likely to lose electrons, resulting in a positive electronegativity. Polyester fiber 1-8's ability to gain or lose electrons is intermediate between the two. Therefore, when nylon membrane 2-6 and PTFE membrane 2-7 are rubbed against polyester fiber 1-8, the polyester fiber 1-8 increases charge transfer, causing both PTFE membrane 2-7 and nylon membrane 2-6 to carry equal and opposite charges, which gradually reach saturation during friction. However, the charges on PTFE membrane 2-7 and nylon membrane 2-6 do not disappear or transfer within a short period of time. At this time, the electrons on the copper grid electrode 1-6 are driven by charge induction, causing current to flow from a high potential to a low potential. When connected to an external circuit, alternating current is generated. This type of power generation structural design utilizes polyester fiber hair 1-8 to indirectly cause friction between the positive and negative friction layers (nylon membrane 2-6 and PTFE membrane 2-7), thereby increasing space utilization and potential difference, thereby increasing electron transfer. In addition, the use of polyester fiber hair 1-8 reduces large-area contact of the friction layer and reduces frictional resistance, making this structure have better conversion efficiency than existing structures under the same external force drive.

[0056] The outer wall of the upper cylinder 1-1 and the upper fan blades 1-3, and the inner wall of the lower cylinder 2-1 and the lower fan blades 2-3 are all provided with inclined tracks with grid-shaped copper electrodes 1-6 attached. The upper inclined track 1-2 and the lower inclined track 2-2 are both provided with balls 4 with a surface of FEP. When the upper cylinder 1 and the lower cylinder 2 rotate, the inclined tracks provide a supporting force for the balls 4, causing the balls 4 to slide or roll on the upper inclined track 1-2 and the lower inclined track 2-2 due to inertia, causing friction and generating irregular alternating current, thereby realizing the second type of TENG power generation.

[0057] The second type of TENG power generation principle is as follows: Figure 8 As shown, grid-shaped copper electrodes are laid on the upper ramp 1-2 and the lower ramp 2-2. These serve as both a conductive layer and a friction layer. FEP and copper have different electron gain and loss abilities: FEP is more likely to lose electrons than copper. Therefore, after friction between the ball 4 and the grid-shaped copper electrodes, both carry equal and opposite charges. However, the charge on the FEP does not vanish or transfer within a short period of time. As the ball 4 rotates with the lower drum 2, the grid-shaped copper electrodes induce unequal positive charges. Once connected to an external circuit, electrons flow through the circuit to maintain potential balance, generating alternating current. This type of power generation design fully utilizes the surface space, increasing output and significantly improving space efficiency.

[0058] The appearance of the fan-blade-shaped ball and the wing-shaped ball both has the ability to be driven by the wind. When the fan-blade-shaped ball and the wing-shaped ball encounter wind, they have the ability to move. The ball will overcome a certain gravity, making it easier to slide, thereby increasing the relative movement of the ball and the inclined track laid with the grid-shaped copper electrode, and improving the output of irregular alternating current; the spherical ball has smaller friction resistance, which can increase the relative movement of the ball and the inclined track laid with the grid-shaped copper electrode, while the cylindrical ball has a larger friction contact area, which can increase the electricity generated when a single ball and the inclined track laid with the grid-shaped copper electrode undergo relative movement.

[0059] 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 filtering unit. At the same time, the collected electrical energy can be stored in the energy storage unit, and then the output voltage amplitude is controlled by the voltage stabilization unit. During this process, the overvoltage protection unit always protects the circuit to ensure the normal operation of the sensing unit, micro-control unit and wireless transmission unit.

[0060] The proposed self-powered bridge cable force monitoring system, based on triboelectric nanogeneration and electromagnetic power generation, is independent of external power sources and can be self-powered, significantly improving the reliability and continuity of bridge health monitoring. This system cleverly utilizes the bridge's own environmental resources, particularly natural wind and wind generated by airflow disturbances caused by vehicles traveling on the bridge. This wind force is captured by the system's energy conversion device, a hybrid energy harvester, and converted into electrical energy to power monitoring equipment such as accelerometers. This overcomes the problem of monitoring interruptions during battery replacement and maintenance, ensuring continuous, real-time monitoring of bridge cable acceleration.

[0061] Those skilled in the art will understand that the foregoing descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art will still be able to modify the technical solutions described in the foregoing examples or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the invention shall be included within the scope of protection of the invention.

Claims

1. A bridge cable force self-powered monitoring system based on triboelectric nano-generation and electromagnetic power generation, characterized in that: include: Hybrid energy harvester, power management circuit, sensor unit, micro-control unit; The hybrid energy harvester converts wind energy into electrical energy, which is then converted into DC voltage through a power management circuit to power the sensor unit and the micro-control unit. The micro-control unit is used to transmit data from the sensor unit. The hybrid energy collector comprises an upper tube, a lower tube, a base, and a ball; the upper tube and the lower tube are coaxially sleeved on the base and can rotate around the central axis; the surface material of the ball is FEP; The upper cylinder comprises: an upper cylinder, an upper inclined rail, an upper fan blade, an upper rib, a coil, a grid-shaped copper electrode, a gap 1, and polyester fiber wool; the upper cylinder is a tubular structure, and its upper surface is fixedly connected to the upper fan blade via an upper rib; a plurality of upper inclined rails are respectively provided on the outer circumference of the upper cylinder and on the upper fan blade, and a grid-shaped copper electrode is laid in the upper inclined rail to accommodate the sliding or rolling of the ball; the grid-shaped copper electrode is attached to the inner wall of the upper cylinder, and a plurality of gaps 1 are evenly provided on the grid copper electrode in the circumferential direction, and polyester fiber wool is arranged in each gap 1; a plurality of coil slots are evenly provided on the inner wall of the upper cylinder in the circumferential direction, and a coil is installed in each coil slot. The coils are divided into two groups according to the position interval. When connected, the coils in the group are connected in series, and after passing through the rectifier bridge, the two groups of coils are connected in parallel; The lower cylinder includes: a lower cylinder, a lower inclined rail, a lower fan blade, a lower rib, a permanent magnet, a nylon membrane, a PTFE membrane, and a gap two; the lower cylinder is a tubular structure, the outer diameter of which is smaller than the inner diameter of the upper cylinder, and the upper cylinder is coaxially sleeved on the outer circumference of the lower cylinder; the lower surface of the lower cylinder is fixedly connected to the lower fan blade through the lower rib, and the torsion direction of the lower fan blade is opposite to that of the upper fan blade; a plurality of lower inclined rails are respectively provided on the inner circumference of the lower cylinder and the lower fan blade, and a grid-shaped copper electrode is laid in the lower inclined rail to accommodate the sliding or rolling of the ball; 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 PTFE membrane are attached at intervals and staggered; a plurality of permanent magnet slots are circumferentially provided on the inner wall of the lower cylinder, and a permanent magnet is installed in each permanent magnet slot, and the permanent magnets are staggered in NS arrangement, and the ratio of the number of permanent magnets to coils is 1:

1.

2. The bridge cable force self-powered monitoring system based on triboelectric nano-power generation and electromagnetic power generation according to claim 1 is characterized in that: The balls are selected from any one of fan-shaped spherical balls, fan-shaped cylindrical balls, wing-shaped spherical balls, and wing-shaped cylindrical balls; The fan-shaped spherical ball bearing comprises a fan blade, a support member, and a spherical ball bearing; a mounting rod of the support member passes through the spherical ball bearing along a diameter, and the spherical ball bearing can rotate with the mounting rod as a rotation axis; the fan blade is fixedly connected to another mounting rod of the support member, and the two mounting rods are parallel and opposite to each other; The fan-blade cylindrical ball bearing comprises a fan blade, a support member, and a cylindrical ball bearing; a mounting rod of the support member passes through the central axis of the cylindrical ball bearing, and the cylindrical ball bearing can rotate with the mounting rod as a rotation axis; the fan blade is fixedly connected to another mounting rod of the support member; The wing-shaped spherical ball includes a wing, a support member, and a spherical ball; a mounting rod of the support member passes through the spherical ball along a diameter, and the spherical ball can rotate with the mounting rod as a rotation axis; the wing is fixedly connected to another mounting rod of the support member; The wing-shaped cylindrical ball includes a wing, a support member, and a cylindrical ball; a mounting rod of the support member passes through the central axis of the cylindrical ball, and the cylindrical ball can rotate with the mounting rod as the rotation axis; the wing is fixedly connected to another mounting rod of the support member.

3. The bridge cable force self-powered monitoring system based on triboelectric nano-power generation and electromagnetic power generation according to claim 1 is characterized in that: The upper ribs have three ends, 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, and the blades intersect at the central axis and have a through hole at the central axis for being sleeved on the base; There are three lower ribs, one end of the three lower ribs intersects and the intersection is located at the central axis of the lower cylinder, and 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, and 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.

4. The bridge cable force self-powered monitoring system based on tribo-nanoelectricity generation and electromagnetic power generation according to claim 1 is characterized in that: The pitch angle of each blade of the upper fan blade and the lower fan blade is 0°, and the projected area angle is 60°.

5. The bridge cable force self-powered monitoring system based on tribo-nanoelectricity 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. The rectification circuit is used to convert alternating current into direct current; the filter is used to reduce ripples in the current and generate an output closer to 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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