A self-powered wearable gait monitoring device
By combining triboelectric nanogenerators and electromagnetic generators, and amplifying motion using a planetary gear mechanism, efficient energy harvesting and gait monitoring are achieved. This solves the problems of low energy capture efficiency and limited functionality in existing technologies, and is suitable for gait analysis and rehabilitation training.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI UNIV
- Filing Date
- 2026-04-13
- Publication Date
- 2026-06-16
AI Technical Summary
Existing human energy harvesting devices struggle to achieve efficient energy capture during low-frequency, high-displacement movements and lack gait monitoring capabilities, resulting in bulky devices and reduced comfort.
By combining triboelectric nanogenerators and electromagnetic generators, and amplifying motion using a planetary gear mechanism, energy is harvested through the relative rotation of the triboelectric material and the electrode pair. Gait monitoring is then performed via electrical signal output, thus reducing the complexity of the device.
It achieves efficient energy harvesting from movements of different frequencies, reduces the complexity and cost of the device, can accurately monitor gait, requires no additional angle sensing elements, and is suitable for gait analysis and rehabilitation training.
Smart Images
Figure CN122004845B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of motion monitoring technology, and in particular to a self-powered wearable gait monitoring device. Background Technology
[0002] Currently, human energy harvesting devices are mainly based on the working principle of triboelectric nanogenerators (TENGs). However, TENGs are primarily designed for low-frequency, irregular mechanical energy movement. When worn on the legs, they may encounter high-frequency movements, for which TENGs struggle to fully capture energy. As for electromagnetic induction technology, the output voltage of an electromagnetic generator (EMG) is proportional to the rate of change of the magnetic field. However, human leg movements are typically low-frequency, high-displacement movements. To extract sufficient electrical energy from low-frequency oscillations, designs must employ heavy and bulky strong magnets and dense coils, or introduce mechanical structures such as levers to amplify the movement speed. This results in bulky energy harvesting devices that significantly increase the user's workload, alter their natural gait, and drastically reduce comfort and practicality. Furthermore, current human energy harvesting devices lack gait monitoring functionality, making their functions relatively limited. Therefore, a self-powered wearable gait monitoring device is urgently needed to address these technical problems. Summary of the Invention
[0003] The purpose of this invention is to provide a self-powered wearable gait monitoring device to solve the problems existing in the prior art. It can capture mechanical energy of different forms and frequencies of leg movements to maximize energy harvesting efficiency and can also achieve gait monitoring.
[0004] To achieve the above objectives, the present invention provides the following solution:
[0005] This invention provides a self-powered wearable gait monitoring device, comprising a first connector, a friction material, an electrode pair, a second connector, a planetary gear mechanism, a magnetic material, and a coil. The first connector is fixedly connected to the lower leg, the friction material is fixedly connected to the first connector, the electrode pair is fixedly connected to the second connector, and the second connector is fixedly connected to the thigh. The electrode pair is sleeved on the outside of the friction material and fitted against it. The friction material includes multiple circumferentially distributed arc-shaped friction plates, and the electrode pair includes multiple circumferentially distributed arc-shaped electrode plates. The planetary gear mechanism includes a gear ring, planetary gears, a planet carrier, and a sun gear. The planet carrier is connected to the first connector, and the first connector can drive the planet carrier to rotate. The planetary gears are rotatably mounted on the planet carrier, and the sun gear meshes with the planetary gears. The gear ring meshes with the planetary gears, and the gear ring is fixed relative to the second connector. The magnetic material is fixedly mounted on the end face of the sun gear, and the coil is fixed relative to the second connector.
[0006] In some embodiments, a housing is also included, which is fitted over the planetary gear mechanism, the magnetic material, and the coil. The housing is fixedly connected to the second connector, the coil is fixedly connected to the housing, and the gear ring is fixedly connected to the housing.
[0007] In some embodiments, the planetary gear mechanism includes a sun gear, a first planet carrier, a second planet carrier, a first planet gear, a second planet gear, a first gear ring, and a second gear ring. The first planet carrier is connected to the first connecting member. The first planet gear is rotatably mounted on the first planet carrier. The first gear ring meshes with the first planet gear. The second planet carrier is meshed with the first planet gear. The second planet gear is rotatably mounted on the second planet carrier. The second gear ring meshes with the second planet gear. The sun gear meshes with the second planet gear. Both the first gear ring and the second gear ring are fixedly connected to the inner wall of the outer casing.
[0008] In some embodiments, a one-way bearing is also included, a fixed disk is provided on the first connecting member, the friction material is fixedly sleeved on the fixed disk, a connecting shaft is fixedly provided at the center of the fixed disk, the connecting shaft is fixedly connected to the inner ring of the one-way bearing, and the outer ring of the one-way bearing is fixedly connected to the planetary carrier.
[0009] In some embodiments, the arc-shaped friction pads are fitted to the outer periphery of the fixed disk and are evenly arranged. The second connector includes a fixing ring. The arc-shaped electrode pads are fitted to the inner wall surface of the fixing ring and are evenly arranged. The number of arc-shaped electrode pads is twice the number of arc-shaped friction pads. Each electrode pair includes two arc-shaped electrode pads.
[0010] In some embodiments, 72 arc-shaped electrode sheets and 36 arc-shaped friction sheets are provided.
[0011] In some embodiments, the first planetary carrier includes a first central shaft and three first gear shafts, the three first gear shafts being fixedly connected to the first central shaft, and the angle between the line connecting any two first gear shafts and the first central shaft being 60 degrees. Three first planetary gears are provided, each rotatably mounted on one of the three first gear shafts. The second planetary carrier includes a second central shaft and three second gear shafts, the three second gear shafts being fixedly connected to the second central shaft, and the angle between the line connecting any two second gear shafts and the second central shaft being 60 degrees. Three second planetary gears are provided, each rotatably mounted on one of the three second gear shafts. A gear is provided on the outer circumferential surface of the second central shaft, and the gear meshes with the first planetary gears.
[0012] In some embodiments, a first bearing is provided between the first axle and the first planetary gear, the first axle is fixedly connected to the inner ring of the first bearing, and the first planetary gear is fixedly sleeved on the outer ring of the first bearing. A second bearing is provided between the second axle and the second planetary gear, the second axle is fixedly connected to the inner ring of the second bearing, and the second planetary gear is fixedly sleeved on the outer ring of the second bearing.
[0013] In some embodiments, the magnetic material is a magnet, and multiple magnets are disposed on the end face of the sun gear, and multiple coils are disposed on the inner end face of the housing, and the number of magnets is the same as the number of coils.
[0014] In some embodiments, the friction material is a fluorinated ethylene propylene copolymer, and the electrode pair is made of aluminum.
[0015] The present invention achieves the following technical effects compared to the prior art:
[0016] The self-powered wearable gait monitoring device provided by this invention combines triboelectric nanogenerators with electromagnetic generators, enabling it to adapt to a wider range of movement frequencies and collect mechanical energy across different frequency bands. The movement of the lower leg is partially converted into energy through triboelectric nanogenerators, while the motion is transmitted through a planetary gear mechanism. The ring gear remains stationary, while the planetary carrier moves, driving the planetary gears, which in turn drive the sun gear, ensuring a certain degree of amplification of the transmission motion. Electromagnetic generation is then achieved by utilizing the motion of cutting magnetic field lines. The device can be designed to combine the electrical energy from triboelectric nanogenerators and electromagnetic generators to drive electrical components. The specific principle of triboelectric nanogenerators is as follows: When the human body begins to move, the lower leg rotates around the knee joint, causing the first connecting piece to rotate synchronously. At this time, the friction material fixed to the first connecting piece rotates. The thigh remains relatively stationary, thus fixing the thigh connection and electrode pair. Due to the relative rotation of the friction material and the electrode pair, they sequentially complete contact, separation, and re-contact, resulting in charge transfer between them, thereby capturing energy and supplying power to the electrical components.
[0017] Furthermore, due to the relative rotation of the friction material and the electrode plate, they sequentially complete contact, separation, and re-contact, resulting in charge transfer and energy capture. Each rotation angle completes a full charge transfer process between the friction material and the electrode pair, outputting an electrical signal that produces a sinusoidal voltage graph with two peaks (one above the other). Each peak represents a fixed rotation angle. Therefore, the number of fixed angles the lower leg has swung can be determined by the output electrical signal, completing the angle measurement. By knowing the central angles of two adjacent arc-shaped friction plates and combining this with the operating voltage graph, the angle traveled can be indirectly determined. The device directly achieves precise measurement of the lower leg swing angle through the electrical signal output of triboelectric nanogenerators, eliminating the need for additional angle sensing elements such as gyroscopes and encoders. This reduces the complexity and cost of the device and solves the problem of redundant functional modules in traditional wearable devices, allowing for direct application in gait analysis, rehabilitation training monitoring, and other scenarios. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is an exploded view of a self-powered wearable gait monitoring device in some embodiments of the present invention;
[0020] Figure 2 This is an assembly diagram of a self-powered wearable gait monitoring device without a housing, as shown in some embodiments of the present invention.
[0021] Figure 3 This is a schematic diagram of the coil arrangement in some embodiments of the present invention;
[0022] Figure 4 This is a schematic diagram of the structure of the triboelectric nanogenerator in some embodiments of the present invention;
[0023] Figure 5 This is a schematic diagram illustrating the working principle of triboelectric nanogenerator in some embodiments of the present invention.
[0024] In the figure: 1-First connector; 2-Connecting shaft; 3-Friction material; 4-Electrode pair; 5-Second connector; 6-One-way bearing; 7-First planetary carrier; 8-First bearing; 9-First planetary gear; 10-First gear ring; 11-Second planetary carrier; 12-Second bearing; 13-Second planetary gear; 14-Second gear ring; 15-Sun gear; 16-Magnetic material; 17-Coil; 18-Outer shell. Detailed Implementation
[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] The purpose of this invention is to provide a self-powered wearable gait monitoring device to solve the problems existing in the prior art. It can capture mechanical energy of different forms and frequencies of leg movements to maximize energy harvesting efficiency and can also achieve gait monitoring.
[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0028] like Figures 1-5As shown, the present invention provides a self-powered wearable gait monitoring device, including a first connector 1, a friction material 3, an electrode pair 4, a second connector 5, a planetary gear mechanism, a magnetic material 16, and a coil 17. The first connector 1 is fixedly connected to the lower leg, the friction material 3 is fixedly connected to the first connector 1, the electrode pair 4 is fixedly connected to the second connector 5, the second connector 5 is fixedly connected to the thigh, the electrode pair 4 is sleeved on the outside of the friction material 3 and fits against it, wherein the friction material 3 includes a plurality of circumferentially distributed arc-shaped friction plates, the electrode pair 4 includes a plurality of circumferentially distributed arc-shaped electrode plates, the planetary gear mechanism includes a gear ring, planetary gears, a planet carrier and a sun gear 15, the planet carrier is connected to the first connector 1, the first connector 1 can drive the planet carrier to rotate, the planetary gears are rotatably mounted on the planet carrier, the sun gear 15 is meshed with the planetary gears, the gear ring is meshed with the planetary gears and the gear ring is fixed relative to the second connector 5, the magnetic material 16 is fixedly mounted on the end face of the sun gear 15, and the coil 17 is fixed relative to the second connector 5.
[0029] The combination of triboelectric nanogenerators and electromagnetic generators can adapt to a wider range of motion frequencies and harvest mechanical energy across different frequency bands. The movement of the lower leg converts some energy through triboelectric nanogenerators and simultaneously transmits motion via a planetary gear mechanism. The ring gear remains stationary while the planetary carrier moves, driving the planetary gears, which in turn drive the sun gear 15, ensuring a certain degree of amplification of the transmission motion. Electromagnetic generation is then achieved by utilizing the motion of cutting magnetic field lines. The electrical energy from both triboelectric nanogenerators and electromagnetic generators can be combined and used to drive electrical components. The specific principle of triboelectric nanogenerators is as follows: When the human body begins to move, the lower leg rotates around the knee joint, causing the first connecting piece 1 to rotate synchronously. At this time, the friction material 3 fixed to the first connecting piece 1 rotates. The thigh remains relatively stationary, thus fixing the thigh connection and electrode pair 4. Due to the relative rotation of the friction material 3 and the electrode pair 4, they sequentially complete contact, separation, and re-contact, resulting in charge transfer and energy harvesting, thus supplying power to the electrical components.
[0030] Furthermore, due to the relative rotation of the friction material 3 and the electrode plate, they sequentially complete the following processes: contact (initial state), separation (when rotating a certain angle, the friction material 3 separates from the left electrode of the first electrode pair and makes full contact with the right electrode of the first electrode pair), and re-contact (when rotating another certain angle, the friction material 3 separates from the right electrode of the first electrode pair and makes full contact with the left electrode of the second electrode pair, i.e., returning to the initial state position; the current direction in this process is opposite to that in the previous process). Charge transfer occurs between them, thus completing energy capture. Each rotation angle completes a full charge transfer process between the friction material 3 and the electrode pair 4. At this time, an output electrical signal is generated, resulting in a voltage graph resembling a sine curve, with two peaks, one above the other. Each peak represents a fixed rotation angle. Therefore, the number of fixed angles the lower leg has swung can be determined by the output electrical signal, completing angle measurement. By knowing the central angles corresponding to two adjacent arc-shaped friction plates and combining this with the operating voltage graph, the angle traveled can be indirectly determined. The device directly achieves precise measurement of the lower leg swing angle by outputting electrical signals generated by triboelectric nanogenerators, eliminating the need for additional angle sensing elements such as gyroscopes and encoders. This reduces the complexity and cost of the device and solves the problem of redundant functional modules in traditional wearable devices. It can be directly applied to scenarios such as gait analysis and rehabilitation training monitoring.
[0031] In some embodiments, the self-powered wearable gait monitoring device further includes a housing 18, which is fitted over the planetary gear mechanism, magnetic material 16, and coil 17. The housing 18 is fixedly connected to the second connector 5, the coil 17 is fixedly connected to the housing 18, and the gear ring is fixedly connected to the housing 18. The housing 18 provides fully or semi-enclosed protection for the planetary gear mechanism, magnetic material 16, and coil 17, effectively preventing impurities such as sweat, dust, and hair from entering the internal transmission and electromagnetic induction areas. This avoids corrosion of the gear meshing surfaces and magnetic material 16 by sweat, reduces the rust rate of the planetary gears, extends the service life of the transmission mechanism, prevents dust from adhering to the coil 17 windings or the surface of the magnetic material 16, and prevents the electromagnetic induction efficiency from decreasing due to increased magnetic circuit losses, ensuring the long-term stability of the output power of the electromagnetic power generation unit. The housing 18 can be made of high-toughness polymers (such as ABS plastic or polycarbonate) or lightweight alloy materials, which can cushion accidental collisions between the knee joint and external objects during exercise, prevent misalignment of the planetary gears and physical damage to the coil 17 windings, and improve the impact resistance of the device. Furthermore, the outer casing 18 provides a rigid fixing reference for the gear ring and coil 17, avoiding the shift in the meshing clearance between the gear ring and the planetary gear, and the deviation in the relative position between the coil 17 and the magnetic material 16 caused by the high-frequency vibration of human movement.
[0032] In some embodiments, the planetary gear mechanism includes a sun gear 15, a first planet carrier 7, a second planet carrier 11, a first planet gear 9, a second planet gear 13, a first ring gear 10, and a second ring gear 14. The first planet carrier 7 is connected to a first connecting member 1. The first planet gear 9 is rotatably mounted on the first planet carrier 7. The first ring gear 10 meshes with the first planet gear 9. The second planet carrier 11 meshes with the first planet gear 9. The second planet gear 13 is rotatably mounted on the second planet carrier 11. The second ring gear 14 meshes with the second planet gear 13. The sun gear 15 meshes with the second planet gear 13. Both the first ring gear 10 and the second ring gear 14 are fixedly connected to the inner wall of the outer casing 18. The two-stage planetary gear mechanism achieves a 25-fold transmission ratio through a series configuration of input from the first planet carrier 7, transmission from the first planet gear 9, relay from the second planet carrier 11, output from the second planet gear 13, and high-speed rotation of the sun gear 15. Each stage has a 5-fold transmission ratio, solving the problems of small amplitude of human joint movement and insufficient electromagnetic power generation. The two-stage planetary gear mechanism adopts a coaxial nested design. The first gear ring 10 and the second gear ring 14 are fixed to the inner wall of the outer shell 18 to form a concentric circle structure. The first planet carrier 7, the second planet carrier 11 and the sun gear 15 are arranged on the same axis. The overall radial dimension increases very little compared with the single-stage configuration, while the axial dimension remains basically unchanged. This achieves compatibility between high-rate transmission and miniaturized structure, resulting in a smaller overall size.
[0033] In some embodiments, the self-powered wearable gait monitoring device further includes a one-way bearing 6. A fixed disk is provided on the first connecting member 1, and friction material 3 is fixedly sleeved on the fixed disk. A connecting shaft 2 is fixedly provided at the center of the fixed disk. The connecting shaft 2 is fixedly connected to the inner ring of the one-way bearing 6, and the outer ring of the one-way bearing 6 is fixedly connected to the planetary carrier, so that the device only receives energy in one direction when the lower leg swings. The one-way bearing 6 realizes a one-way locking function, which can shield the invalid energy input in the reset direction and avoid the planetary gear mechanism from generating idle loss in reverse movement. The sun gear 15 of the electromagnetic power generation rotates at high speed in one direction, the magnetic flux change rate is more uniform, the output power fluctuation amplitude is reduced significantly, and the operational stability is improved.
[0034] In some embodiments, the friction material 3 includes a plurality of arc-shaped friction plates, which are uniformly arranged and adhered to the outer periphery of the fixed disk. The electrode pair 4 includes a plurality of arc-shaped electrode plates. The second connecting member 5 includes a fixing ring, and the arc-shaped electrode plates are uniformly arranged and adhered to the inner wall surface of the fixing ring. The number of arc-shaped electrode plates is twice the number of arc-shaped friction plates. Two adjacent arc-shaped electrode plates form an electrode pair 4. There are 72 arc-shaped electrode plates and 36 arc-shaped friction plates, meaning the central angle between two adjacent arc-shaped friction plates is 10 degrees. Knowing the central angle between two adjacent arc-shaped friction plates allows us to indirectly determine the angle at which the friction was applied.
[0035] Due to relative rotation, the friction material 3 and the electrode plate sequentially complete contact (initial state), separation (when rotating 5°, the friction material 3 separates from the left electrode of the first electrode pair and makes full contact with the right electrode of the first electrode pair), and re-contact (when rotating 10°, the friction material 3 separates from the right electrode of the first electrode pair and makes full contact with the left electrode of the second electrode pair, i.e., returning to the initial state position; the current direction in this process is opposite to the previous process). Charge transfer occurs between them, thus completing energy capture. Every 10° of rotation, a complete charge transfer process is completed between the friction material 3 and the electrode pair 4. At this time, an electrical signal is output, resulting in a voltage graph similar to a sine curve, with one peak and one trough. Each peak represents a 5° rotation. Therefore, the number of 5° swings of the lower leg can be determined by the output electrical signal, completing the angle measurement. The device directly achieves accurate measurement of the lower leg swing angle through the electrical signal output of triboelectric nanogenerators, without the need for additional angle sensing elements such as gyroscopes and encoders. This reduces the complexity and cost of the device and solves the problem of redundant functional modules in traditional wearable devices. It can be directly applied to gait analysis, rehabilitation training monitoring, and other scenarios. The ratio of 36 arc-shaped friction plates to 72 arc-shaped electrode plates ensures that a complete charge transfer is completed every 10° rotation of the lower leg, increasing the charge transfer frequency compared to traditional friction structures with fewer plates. This high-frequency contact and separation process significantly increases the total charge transfer, thereby enhancing the output power of triboelectric nanogenerators. Simultaneously, the higher pulse density of the output electrical signal facilitates energy harvesting and utilization in subsequent rectification and voltage regulation circuits.
[0036] In some embodiments, the first planetary carrier 7 includes a first central shaft and three first gear shafts, the three first gear shafts being fixedly connected to the first central shaft, and the angle between the lines connecting any two first gear shafts and the first central shaft being 60 degrees. Three first planetary gears 9 are provided, each rotatably mounted on one of the three first gear shafts. The second planetary carrier 11 includes a second central shaft and three second gear shafts, the three second gear shafts being fixedly connected to the second central shaft, and the angle between the lines connecting any two second gear shafts and the second central shaft being 60 degrees. Three second planetary gears 13 are provided, each rotatably mounted on one of the three second gear shafts. A gear is provided on the outer circumferential surface of the second central shaft, and the gear meshes with the first planetary gears 9. Both the first planetary carrier 7 and the second planetary carrier 11 adopt a configuration where three planetary gears are symmetrically arranged at a 60-degree angle, so that the input load and output load are evenly distributed to the meshing surfaces of the three planetary gears and the ring gear and sun gear 15, reducing the contact stress on a single meshing tooth surface.
[0037] In some embodiments, a first bearing 8 is provided between the first axle and the first planetary gear 9, with the inner ring of the first axle and the first bearing 8 fixedly connected. The first planetary gear 9 is fixedly sleeved on the outer ring of the first bearing 8. A second bearing 12 is provided between the second axle and the second planetary gear 13, with the inner ring of the second axle and the second bearing 12 fixedly connected. The second planetary gear 13 is fixedly sleeved on the outer ring of the second bearing 12. The bearing between the planetary gear and the axle transforms traditional sliding friction into rolling friction, reducing the coefficient of friction, decreasing losses, and reducing transmission resistance, thus making the planetary gear run more smoothly.
[0038] In some embodiments, the magnetic material 16 is a magnet, and multiple magnets are disposed on the end face of the sun gear 15, while multiple coils 17 are disposed on the inner end face of the outer casing 18, with the number of magnets matching the number of coils 17. The one-to-one correspondence between multiple sets of magnets and coils 17 allows the sun gear 15 to simultaneously drive multiple magnets to cut the magnetic field lines of the corresponding coils 17 when rotating, increasing the total change in magnetic flux per unit time compared to a single set of magnetic coils 17. The uniform arrangement of multiple magnets on the end face of the sun gear 15 forms a ring-shaped distributed magnetic field, avoiding the magnetic field concentration and waste associated with a single magnet structure. The ring-shaped array of corresponding coils 17 completely covers the magnetic field range, improving magnetic field energy utilization and enhancing the conversion efficiency of mechanical energy to electrical energy. The uniform ring-shaped arrangement of multiple sets of magnetic coils 17 ensures that at any rotation angle, at least one set of magnets and coils 17 are effectively coupled, avoiding power generation interruptions caused by the rotational dead zone (the angle range where there is no relative movement between the magnet and coil 17) of a single structure, achieving uninterrupted power output throughout the entire cycle. The output of a single magnetic coil 17 is low-frequency pulsed electrical energy (e.g., when the sun gear rotates at 100 rad / s, the output frequency of a single coil is 16 Hz). Multiple magnetic coils 17, through phase-staggered arrangement (the angle between adjacent magnets / coils is 360° / n), can achieve high-frequency superposition of pulsed electrical energy. Taking eight magnetic coils 17 as an example, the output pulse frequency can be increased to 128 Hz. After rectification and filtering, the ripple coefficient of the output voltage can be reduced from 40% of a single coil to below 5%, achieving a stable electrical energy output close to DC. This eliminates the need for additional large-capacity energy storage capacitors to directly match the power supply requirements of low-power electronic components.
[0039] In some embodiments, the friction material 3 is fluorinated ethylene propylene (FEP), and the electrode pair 4 is made of aluminum. The electron affinity of FEP (approximately -2.0 eV) is much higher than that of aluminum (approximately -0.8 eV), resulting in a significant charge transfer effect upon contact. The FEP surface readily captures a large number of negative charges, while the aluminum electrode surface is enriched with positive charges. The charge density during a single contact and separation process can reach 10–15 μC / m². 2Compared to traditional PTFE-copper friction combinations, this method improves efficiency by 30% to 50%, significantly increasing the output voltage and power density of triboelectric nanogenerators. It also addresses the issues of insufficient charge transfer and low power generation efficiency associated with low-affinity potential difference material combinations. PTFE exhibits excellent chemical inertness, resisting corrosive media such as salt and lactic acid in human sweat. Furthermore, it is resistant to high and low temperatures, showing no performance degradation in outdoor high-temperature, humid, or low-temperature environments. This solves the problem of traditional friction materials (such as polypropylene) being susceptible to a sharp drop in power generation efficiency due to humidity. The aluminum electrode can form a dense oxide film through anodic oxidation, effectively resisting sweat corrosion and air oxidation. The conductivity and charge storage capacity of the electrode surface remain stable over the long term, avoiding the increased contact resistance caused by the oxidation and rusting of copper electrodes.
[0040] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.
Claims
1. A self-powered wearable gait monitoring device, characterized in that: The device includes a first connector, a friction material, an electrode pair, a second connector, a planetary gear mechanism, a magnetic material, and a coil. The first connector is used for fixed connection with the lower leg. The friction material is fixedly connected to the first connector. The electrode pair is fixedly connected to the second connector. The second connector is used for fixed connection with the thigh. The electrode pair is sleeved on the outside of the friction material and fits snugly. The friction material includes multiple circumferentially distributed arc-shaped friction plates. The electrode pair includes multiple circumferentially distributed arc-shaped electrode plates. The planetary gear mechanism includes a gear ring, planetary gears, a planet carrier, and a sun gear. The planet carrier is connected to the first connector, and the first connector can drive the planet carrier to rotate. The planetary gears are rotatably mounted on the planet carrier. The sun gear meshes with the planetary gears. The gear ring meshes with the planetary gears and is fixed relative to the second connector. The magnetic material is fixedly mounted on the end face of the sun gear. The coil is fixed relative to the second connector.
2. The self-powered wearable gait monitoring device according to claim 1, characterized in that: It also includes a housing, which is fitted over the planetary gear mechanism, the magnetic material and the coil. The housing is fixedly connected to the second connector, the coil is fixedly connected to the housing, and the gear ring is fixedly connected to the housing.
3. The self-powered wearable gait monitoring device according to claim 2, characterized in that: The planetary gear mechanism includes a sun gear, a first planet carrier, a second planet carrier, a first planet gear, a second planet gear, a first gear ring, and a second gear ring. The first planet carrier is connected to the first connecting member. The first planet gear is rotatably mounted on the first planet carrier. The first gear ring meshes with the first planet gear. The second planet carrier is meshed with the first planet gear. The second planet gear is rotatably mounted on the second planet carrier. The second gear ring meshes with the second planet gear. The sun gear meshes with the second planet gear. Both the first gear ring and the second gear ring are fixedly connected to the inner wall of the outer casing.
4. The self-powered wearable gait monitoring device according to claim 1, characterized in that: It also includes a one-way bearing, a fixed disk is provided on the first connecting member, the friction material is fixedly sleeved on the fixed disk, a connecting shaft is fixedly provided at the center of the fixed disk, the connecting shaft is fixedly connected to the inner ring of the one-way bearing, and the outer ring of the one-way bearing is fixedly connected to the planetary carrier.
5. The self-powered wearable gait monitoring device according to claim 4, characterized in that: The arc-shaped friction pads are attached to the outer periphery of the fixed disk and are evenly arranged. The second connector includes a fixed ring. The arc-shaped electrode pads are attached to the inner wall surface of the fixed ring and are evenly arranged. The number of arc-shaped electrode pads is twice the number of arc-shaped friction pads. Each electrode pair includes two arc-shaped electrode pads.
6. The self-powered wearable gait monitoring device according to claim 5, characterized in that: There are 72 arc-shaped electrode plates and 36 arc-shaped friction plates.
7. The self-powered wearable gait monitoring device according to claim 3, characterized in that: The first planetary carrier includes a first central shaft and three first gear shafts, the three first gear shafts being fixedly connected to the first central shaft, and the angle between the line connecting any two first gear shafts and the first central shaft being 60 degrees. Three first planetary gears are provided, each rotatably mounted on one of the three first gear shafts. The second planetary carrier includes a second central shaft and three second gear shafts, the three second gear shafts being fixedly connected to the second central shaft, and the angle between the line connecting any two second gear shafts and the second central shaft being 60 degrees. Three second planetary gears are provided, each rotatably mounted on one of the three second gear shafts. A gear is provided on the outer circumferential surface of the second central shaft, and the gear meshes with the first planetary gears.
8. The self-powered wearable gait monitoring device according to claim 7, characterized in that: A first bearing is provided between the first axle and the first planetary gear. The first axle is fixedly connected to the inner ring of the first bearing, and the first planetary gear is fixedly sleeved on the outer ring of the first bearing. A second bearing is provided between the second axle and the second planetary gear. The second axle is fixedly connected to the inner ring of the second bearing, and the second planetary gear is fixedly sleeved on the outer ring of the second bearing.
9. The self-powered wearable gait monitoring device according to claim 2, characterized in that: The magnetic material is a magnet, and multiple magnets are provided on the end face of the sun gear. Multiple coils are provided on the inner end face of the outer casing, and the number of magnets is the same as the number of coils.
10. The self-powered wearable gait monitoring device according to claim 1, characterized in that: The friction material is fluorinated ethylene propylene copolymer, and the electrode pair is made of aluminum.