Self-driven bistable intelligent bracelet

Abstract

The invention discloses a self-driven bistable state intelligent bracelet. The bracelet comprises a bracelet shell, and the bracelet shell is of a symmetrical nested structure formed by nesting an outer ring, an inner lantern ring, an outer fixing ring and an inner fixing ring; a flexible negative stiffness bending beam is arranged between the outer fixing ring and the inner fixing ring, and the two ends of the flexible negative stiffness bending beam are hinged to the outer fixing ring and the inner fixing ring respectively. The two ends of the outer fixing ring are each provided with a bistable power generation module, and the two bistable power generation modules are arranged in a mirror image mode. The bistable structure formed by the flexible negative stiffness bending beams can convert low-frequency and irregular mechanical energy generated by human body movement into large-amplitude transition movement, so that the friction nanometer power generation module is efficiently driven, the energy conversion efficiency under the low-frequency excitation condition is remarkably improved, the endurance problem of the bracelet is fundamentally solved, and the safety of the bracelet is improved. The method is suitable for long-term health monitoring, motion tracking and other scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wearable devices and energy harvesting, and particularly relates to a self-driven bistable smart bracelet. BACKGROUND

[0002] With the rapid development of the Internet of Things and intelligent terminals, as a typical wearable device, the bracelet plays an increasingly important role in the fields of health monitoring, sports tracking and human-computer interaction. However, the high integration of device functions and the continuous operation requirements pose a serious challenge to its power supply system. The mainstream bracelets on the market generally use chemical power sources such as lithium-ion batteries as energy sources, which have problems such as limited capacity, short cycle life, frequent charging or battery replacement, and seriously restrict the long-term endurance and user experience of the device. In addition, the environmental pollution and resource waste problems caused by abandoned batteries are increasingly prominent, and green and sustainable alternative power supply solutions are urgently needed. The mechanical energy generated by the human body in daily activities, such as limb swinging and joint bending, is a widely existing and easily accessible renewable energy source. If it can be efficiently converted into electrical energy, it is expected to realize the self-powered operation of electronic devices. However, human motion has the characteristics of low frequency, large amplitude variation, irregular motion mode, etc. Traditional energy collection devices based on resonance principle, such as electromagnetic, piezoelectric and electrostatic vibration energy collectors, have significantly reduced energy conversion efficiency under low-frequency excitation conditions, making it difficult to meet the actual application requirements.

[0003] In recent years, as a new energy conversion mechanism, the friction nanogenerator technology (TENG) has shown great potential in the field of micro-energy due to its wide selection of materials, flexible structure design, and high energy density. Based on the contact electrification and electrostatic induction coupling effect, it can directly convert mechanical energy in the environment into electrical energy. Existing research has explored the application of TENG in wearable devices, for example, by using flexible friction layers to collect human motion energy. However, the traditional TENG structure is mostly a linear vibration system, and its output performance is limited under low-frequency and small-amplitude excitation, resulting in unsatisfactory power generation efficiency and limiting its practical application effect in human energy harvesting.

[0004] To improve the energy harvesting performance of TENG in a low-frequency environment, researchers have begun to introduce nonlinear dynamic mechanisms; Among them, the bistable structure has two stable equilibrium states, and can produce large amplitude inter-well motion under external excitation, thereby significantly enhancing the response capability to low-frequency and wide-frequency vibration, and has become one of the effective ways to improve the environmental adaptability of energy collectors; In the prior art, some studies have combined bistable structures with piezoelectric or electromagnetic power generation mechanisms to improve the efficiency of vibration energy harvesting; For example, Shengxi Zhou et al. proposed a bistable piezoelectric energy harvesting method, and Junyi Cao et al. developed a bistable magnetoelastic energy harvesting system; However, there is still a lack of research on the integration and miniaturization design of the combination of bistable structure and friction nanometer power generation technology for specific application scenarios of the bracelet; The existing scheme has shortcomings in the compatibility of structural integration and wearing comfort. SUMMARY

[0005] To solve the above technical problems, the technical scheme adopted by the present application is: a self-driven bistable intelligent bracelet, characterized in that it comprises a bracelet shell, the bracelet shell is a symmetrical nested structure nested by an outer ring, an inner ring, an outer fixed ring and an inner fixed ring, and the inner ring, the inner fixed ring, the outer fixed ring and the outer ring are arranged concentrically, and the outer fixed ring and the outer ring are fixedly connected, and the inner ring and the inner fixed ring are also fixedly connected.

[0006] A flexible negative stiffness curved beam is arranged between the outer fixed ring and the inner fixed ring, and the two ends of the flexible negative stiffness curved beam are hingedly connected with the outer fixed ring and the inner fixed ring respectively.

[0007] Double-stable power generation modules are arranged at both ends of the outer fixed ring, the double-stable power generation module comprises an outer plate, the outer plate is fixedly connected with the outer fixed ring, an inner plate is arranged on the side of the outer plate close to the flexible negative stiffness curved beam, the inner plate is fixedly connected with the inner fixed ring, and a friction film is arranged between the inner plate and the outer plate.

[0008] As a preferred technical scheme of the present application, the friction film is a three-layer structure, comprising a layer of FEP film in the middle, and a layer of copper film is arranged on both sides of the FEP film.

[0009] As a preferred technical scheme of the present application, the copper film close to the inner plate is attached to the inner plate, the copper film close to the outer plate is attached to the outer plate, and the FEP film is fixedly connected with the copper film attached to the inner plate.

[0010] As a preferred technical scheme of the present application, the inner plate and the outer plate are annular, and the FEP film and the copper film are fan-shaped.

[0011] As a preferred technical scheme of the present application, the flexible negative stiffness curved beam is a pre-buckling structure, which has two stable equilibrium states and is realized by the negative stiffness characteristic of the flexible negative stiffness curved beam.

[0012] As a preferred technical scheme of the present application, the flexible negative stiffness curved beam coincides with the radial direction of the bracelet at the initial point position, at which the flexible negative stiffness curved beam is at the unstable equilibrium point of the bistable bracelet, and when the flexible negative stiffness curved beam is at the extreme points on the left and right sides of the initial point position, the flexible negative stiffness curved beam is at the stable equilibrium point of the bistable bracelet.

[0013] As a preferred technical scheme of the present application, the outer ring, the inner ring, the outer fixed ring, the inner fixed ring, the outer plate and the inner plate are all made of insulating materials.

[0014] As a preferred technical scheme of the present application, the FEP film is electrically connected with the rectifier of the bracelet to realize continuous energy supply to the bracelet.

[0015] The present application has the following advantages:

[0016] Firstly, the bistable structure composed of the flexible negative stiffness curved beam is creatively combined with negative stiffness and friction power generation, and the low-frequency and irregular mechanical energy generated by human motion is converted into large-amplitude transition motion through the negative stiffness characteristic of the flexible negative stiffness curved beam, thereby efficiently driving the friction nanometer power generation module, significantly improving the energy conversion efficiency under low-frequency excitation conditions, fundamentally solving the bracelet endurance problem, and being suitable for long-term health monitoring and motion tracking scenes.

[0017] Secondly, the present application can flexibly change the potential energy barrier height of the bistable structure by adjusting the distance between the inner and outer rings, the stiffness and geometric parameters of the flexible negative stiffness curved beam, thereby adapting to human motion excitation of different intensities, enhancing the environmental adaptability and energy collection bandwidth of the bracelet under different motion states, and pushing out different models of products to make the application more universal. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present application will be further described below in combination with the drawings and examples.

[0019] Figure 1 is the front view of the overall structure of the present application.

[0020] Figure 2 is the exploded view of the overall structure of the present application.

[0021] Figure 3 is the corresponding potential energy-angle displacement curve of the present application.

[0022] In the diagram: 1. Wristband housing; 11. Outer ring; 12. Inner ring; 13. Outer fixed ring; 14. Inner fixed ring; 15. Flexible negative stiffness bending beam; 2. Bistable power generation module; 21. Outer plate; 22. Inner plate; 23. Friction film; 231. FEP film; 232. Copper film; U. Potential energy; X. Angular displacement. Detailed Implementation

[0023] The embodiments of the present invention are described in detail below.

[0024] See Figure 1 and Figure 2 The present invention provides a self-driven bistable smart bracelet, including a bracelet shell 1. The bracelet shell 1 is a symmetrical nested structure composed of an outer ring 11, an inner ring 12, an outer fixing ring 13, and an inner fixing ring 14. The inner ring 12, inner fixing ring 14, outer fixing ring 13, and outer ring 11 are arranged concentrically along the radial direction of the bracelet from the inside to the outside. The outer fixing ring 13 and outer ring 11 are fixedly connected, and the inner ring 12 and inner fixing ring 14 are also fixedly connected. A flexible negative stiffness bending beam 15 is provided between the outer fixing ring 13 and the inner fixing ring 14. The two ends of the flexible negative stiffness bending beam 15 are respectively hinged to the outer fixing ring and the inner fixing ring.

[0025] See Figure 1 and Figure 2 The outer fixing ring 13 has bistable power generation modules 2 at both ends, and the two bistable power generation modules 2 are arranged in a mirror image. The bistable power generation module 2 includes an outer plate 21, which is fixedly connected to the outer fixing ring 13. An inner plate 22 is provided on the side of the outer plate 21 near the flexible negative stiffness bending beam 15, and the inner plate 22 is fixedly connected to the inner fixing ring 14. A friction membrane 23 is provided between the inner plate 22 and the outer plate 21. The friction membrane 23 has a three-layer structure, including a middle FEP membrane 231 and a copper membrane 232 on both sides of the FEP membrane 231. The copper membrane 232 near the inner plate 22 is attached to the inner plate 22, and the copper membrane 232 near the outer plate 21 is attached to the outer plate 21. The FEP membrane 231 is fixedly connected to the copper membrane 232 attached to the inner plate 22. The inner plate 22 and the outer plate 21 are annular, and the FEP membrane 231 and the copper membrane 232 are fan-shaped.

[0026] See Figure 1 and Figure 2The flexible negative stiffness bending beam 15 is a pre-buckling structure with two stable equilibrium states, achieved through its negative stiffness characteristics. The initial position is when the flexible negative stiffness bending beam 15 coincides with the radial direction of the wristband; at this point, the flexible negative stiffness bending beam 15 is at an unstable equilibrium point of the bistable wristband. When the flexible negative stiffness bending beam 15 is located at the extreme points on either side of the initial position, it is at a stable equilibrium point of the bistable wristband. The potential energy barrier height of the flexible negative stiffness bending beam 15 is adjusted by regulating the distance between the inner and outer fixed rings, as well as the stiffness and geometric parameters of the flexible negative stiffness bending beam 15. The outer ring 11, inner ring 12, outer fixed ring 13, inner fixed ring 14, outer plate 21, and inner plate 22 are all made of insulating material. The FEP membrane 231 is electrically connected to the wristband's rectifier.

[0027] In this embodiment, the outer ring 5, inner ring 3, outer fixing ring 4, inner fixing ring 2, outer plate 8 and inner plate 7 are all made of insulating materials to avoid electrical short circuits and ensure safety; the flexible negative stiffness bending beam 15 is made of elastic material and has good fatigue life and deformation capacity.

[0028] Specific working process: During wear, low-frequency, irregular mechanical energy generated by human movement (such as arm swinging and rotation) is transmitted to the bracelet shell 1, causing slight relative movement between the outer fixing ring 13 and the inner fixing ring 14; the flexible negative stiffness bending beam 15 undergoes elastic deformation under these slight external excitations and generates large-amplitude inter-well transition motions (such as...) using bistable characteristics. Figure 3 As shown, the bistable system formed by the flexible negative stiffness bending beam 15 has two stable equilibrium points corresponding to potential energy traps, and an unstable equilibrium point in the middle corresponding to a potential energy barrier. When the external excitation energy is sufficient to enable the system to cross the potential energy barrier, the flexible negative stiffness bending beam 15 will generate a large-scale, high-speed inter-trap transition motion. This transition motion drives the friction film 236 between the inner plate 22 and the outer plate 21 to slide relative to each other. That is, the FEP film 231 and the copper film 232 generate charge transfer due to contact electrification and electrostatic induction, thereby outputting electrical energy. Since the bistable structure converts low-frequency excitation into large-scale motion, it significantly improves the efficiency of triboelectric nano-power generation and realizes continuous self-powered power supply.

[0029] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention, which are still covered within the protection scope of the present invention.

Claims

1. A self-driven bistable smart bracelet, characterized in that, The bracelet includes a housing, which is a symmetrical nested structure consisting of an outer ring, an inner ring, an outer fixing ring, and an inner fixing ring. The inner ring, inner fixing ring, outer fixing ring, and outer ring are arranged concentrically along the radial direction of the bracelet from the inside to the outside. The outer fixing ring and the outer ring are fixedly connected, and the inner ring and the inner fixing ring are also fixedly connected. A flexible negative stiffness bending beam is provided between the outer fixing ring and the inner fixing ring, and the two ends of the flexible negative stiffness bending beam are respectively hinged to the outer fixing ring and the inner fixing ring. Both ends of the outer fixed ring are provided with bistable power generation modules, and the two bistable power generation modules are arranged in a mirror image. The bistable power generation module includes an outer plate, which is fixedly connected to an outer fixing ring. An inner plate is provided on the side of the outer plate near the flexible negative stiffness bending beam, and the inner plate is fixedly connected to an inner fixing ring. A friction film is provided between the inner plate and the outer plate.

2. The self-driven bistable smart bracelet according to claim 1, characterized in that, The friction film has a three-layer structure, including a middle FEP film and a copper film on both sides of the FEP film.

3. The self-driven bistable smart bracelet according to claim 2, characterized in that: The copper film near the inner plate is attached to the inner plate, and the copper film near the outer plate is attached to the outer plate. The FEP film is fixedly connected to the copper film attached to the inner plate.

4. A self-driven bistable smart bracelet according to claim 3, characterized in that: The inner and outer plates are annular, while the FEP film and copper film are fan-shaped rings.

5. A self-driven bistable smart bracelet according to claim 1, characterized in that: The flexible negative stiffness bending beam is a pre-buckling structure with two stable equilibrium states, which are achieved through the negative stiffness characteristics of the flexible negative stiffness bending beam.

6. A self-driven bistable smart bracelet according to claim 5, characterized in that, The initial point is when the flexible negative stiffness bending beam coincides with the radial direction of the wristband. At this point, the flexible negative stiffness bending beam is at an unstable equilibrium point of the bistable wristband. When the flexible negative stiffness bending beam is at the extreme points on the left and right sides of the initial point, the flexible negative stiffness bending beam is at a stable equilibrium point of the bistable wristband.

7. A self-driven bistable smart bracelet according to claim 5, characterized in that, The potential energy barrier height of the flexible negative stiffness bending beam is adjusted by adapting the spacing between the inner and outer fixed rings, as well as the stiffness and geometric parameters of the flexible negative stiffness bending beam.

8. A self-driven bistable smart bracelet according to claim 1, characterized in that, The outer ring, inner ring, outer fixing ring, inner fixing ring, outer plate, and inner plate are all made of insulating material.

9. A self-driven bistable smart bracelet according to claim 2, wherein the FEP film is electrically connected to the rectifier of the bracelet.

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