Multistage helical weave based sensor, method of manufacture and applications

Abstract

This application discloses a multi-level helical braided base sensor, its fabrication method, and its application, aiming to solve the problems of inaccurate riding posture monitoring and limited application environments of existing flexible braided base sensors used in bicycle equipment. The sensor includes a primary helical skeleton composed of a rigid support material, and a secondary helical layer formed by alternating wrapping of positive and negative electrode fiber yarns on its surface. Both the positive and negative electrode yarns are core-shell structures with an outer functional fiber layer and an inner conductive material layer. The fabrication method includes: braiding the core-shell yarns; alternately wrapping the two types of core-shell yarns on the surface of the rigid support material at specific angles and intervals; and winding them into a helical spring shape. This sensor has a unique structure, enabling both high-sensitivity capacitive sensing and efficient triboelectric nanogenerators. It possesses excellent elasticity, durability, and functional integration, making it suitable for scenarios requiring self-powered sensing, such as smart wearables and motion monitoring.

Description

Technical Field

[0001] This application relates to the fields of flexible electronics and smart textile technology, specifically to a multi-level helical structure braided base sensor, its preparation method, and its application. Background Technology

[0002] With the rapid development of flexible electronics and wearable technology, the application fields of smart textiles are constantly expanding, especially showing great potential in sports and health monitoring, human-computer interaction, and intelligent safety equipment. Among them, textile-based flexible sensors, which can convert mechanical stimuli (such as pressure and strain) into electrical signals, are one of the core components. An ideal flexible sensor not only needs excellent sensing performance, but also good wearability, environmental adaptability, and sustainable operation.

[0003] Currently, flexible sensors based on textile materials mainly follow sensing principles such as resistive, capacitive, or piezoelectric sensing. However, existing technologies generally suffer from several bottlenecks: First, most textile sensors have relatively simple structures (such as planar fabrics or parallel yarn structures), with a single deformation mode, making it difficult to achieve stable and high-fidelity conformal fit with the complex curves of the human body, resulting in inaccurate or incomplete signal acquisition. Second, these sensors are usually single-function, with few integrating high-precision sensing and efficient energy harvesting. This means that systems relying on such sensors often still require external power, limiting their application in passive or long-term outdoor scenarios. Furthermore, the signal output of traditional sensors is susceptible to interference from environmental temperature and humidity, as well as multi-axial force coupling, and their stability and reliability need improvement.

[0004] For example, in the field of smart cycling equipment, existing solutions mostly use external sensors or simple textile pressure pads. The former suffers from the problem of a rigid structure being incompatible with flexible equipment and relying on batteries for power; the latter suffers from low sensitivity, significant signal interference, and a lack of self-powering capability. Although some research has attempted to combine triboelectric nanogenerators with textiles, their structures are mostly simple layered or parallel weaves, resulting in insufficient energy conversion efficiency and signal output stability, and difficulty in maintaining stable sensing performance under complex deformation.

[0005] Therefore, there is an urgent need in this field for a novel textile-based sensor and its fabrication method. This sensor should have a structural design that can adaptively fit complex curved surfaces, achieve high sensitivity and multi-mode sensing, and at the same time have the ability to efficiently collect environmental mechanical energy, thereby providing core component support for building a truly self-powered and highly reliable intelligent wearable system. Summary of the Invention

[0006] The main objective of this application is to provide a multi-level spiral structure braided base sensor, which includes: a rigid support material (1), a positive electrode fiber material braided yarn (2), and a negative electrode fiber material braided yarn (3).

[0007] The rigid support material (1) is wound to form a helical spring-shaped main structure;

[0008] The positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are spirally wrapped around the surface of the rigid support material (1) in an alternating and adjacent manner, forming a spiral wrapping layer together. They are wound into a spiral structure by a winding machine, and after winding, a multi-level spiral structure braided base sensor is formed.

[0009] The positive electrode fiber material braided yarn (2) has a core-spun braided structure, with its outer layer woven from electropositive fiber material (4) and its inner layer composed of conductive material (6);

[0010] The negative electrode fiber material braided yarn (3) has a core-spun braided structure, with its outer layer woven from electronegative fiber material (5) and its inner layer composed of conductive material (6).

[0011] In one embodiment, the electropositive fiber material (4) is a fibrous material located at a leading position in the triboelectric sequence, including but not limited to at least one of nylon and wool;

[0012] The electronegative fiber material (5) is a fiber material that is ranked low in the triboelectric sequence, including but not limited to at least one of polyimide and polyethylene.

[0013] In one embodiment, the conductive material (6) is at least one selected from, but not limited to, silver-plated conductive yarn and conductive metal wire.

[0014] In one embodiment, the rigid support material (1) is a metal alloy wire, including but not limited to at least one of copper wire and iron wire.

[0015] In one embodiment, the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are wrapped around the surface of the rigid support material (1) with the same wrapping angle and wrapping interval, and the wrapping length and wrapping density of the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are the same.

[0016] A method for fabricating a braided base sensor with a multi-level helical structure, the method comprising the following steps:

[0017] S1: Multiple positively charged fiber yarns are used as the outer layer and a conductive material (6) is used as the inner layer. The positive fiber material braided yarn (2) is formed by braiding with a braiding machine. Multiple negatively charged fiber yarns are used as the outer layer and a conductive material (6) is used as the inner layer. The negative fiber material braided yarn (3) is formed by braiding with the braiding machine.

[0018] S2: The positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are wrapped alternately and adjacently on the surface of a rigid support material (1) at a preset wrapping angle and wrapping interval;

[0019] S3: The rigid support material (1) wrapped with the braided yarn in step S2 is wound into a spiral spring-like structure to obtain the braided base sensor with the multi-level spiral structure.

[0020] In one embodiment, the weaving speed of the weaving machine in step S1 is set to 400-600 r / min;

[0021] The linear density of the electropositive fiber material (4) is 30-60 tex, the linear density of the electronegative fiber material (5) is 30-60 tex, and the linear density of the conductive material (6) is 30-40 tex.

[0022] In one embodiment, the wrapping angle in step S2 is between 40° and 60°, the wrapping interval is 20-40 mm, the coating density is 5-20 r / layer, and the diameter of the spiral spring-shaped structure obtained after winding in step S3 is 8-12 mm and the length is 10-40 mm.

[0023] The application of a multi-level helical structure braided base sensor in bicycle motion monitoring and self-powered lighting includes:

[0024] Multiple braided base sensors are integrated in an array inside the bicycle saddle to form a distributed intelligent pressure sensing system.

[0025] The woven base sensor is used to monitor the distribution and dynamic changes of seat pressure during cycling in real time to detect and evaluate cycling posture; and / or to collect the mechanical energy generated in the saddle during cycling and convert it into electrical energy to power the bicycle lighting system.

[0026] Therefore, this application has the following beneficial effects:

[0027] This application discloses a multi-level helical braided base sensor and its fabrication method, belonging to the field of flexible electronics and smart textiles. It aims to solve the problems of inaccurate riding posture monitoring and limited application environments in existing flexible braided base sensors used in bicycle equipment. The sensor includes a primary helical skeleton composed of a rigid support material (1), and a secondary helical functional layer formed by alternating wrapping of positive and negative electrode fiber braided yarns (2 and 3) on its surface. Both the positive and negative electrode yarns are core-spun structures with an outer functional fiber and an inner conductive material (6). The fabrication method includes: S1. braiding the core-spun yarn; S2. alternately wrapping the two types of core-spun yarns at specific angles and intervals on the surface of the rigid support material; S3. winding into a helical spring shape. This sensor has a unique structure, enabling both high-sensitivity capacitive sensing and efficient triboelectric nanogenerators. It possesses excellent elasticity, durability, and functional integration, making it suitable for scenarios requiring self-powered sensing, such as smart wearables and motion monitoring. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A three-dimensional schematic diagram of the overall structure of a braided base sensor with a multi-level helical structure;

[0030] Figure 2 This is a schematic diagram of the fabrication process of a braided sensor.

[0031] Figure 3 a and Figure 3 b are the sensitivity comparison curves and open-circuit voltage comparison curves of sensors with different wrapping densities prepared in the embodiments of this application, respectively;

[0032] Figure 4 a and Figure 4 b represents the sensitivity comparison curve and open-circuit voltage comparison curve of sensors with different wrapping lengths (effective number of turns) prepared in the embodiments of this application;

[0033] The labels in the diagram are as follows: 1- Rigid support material; 2- Positive electrode fiber material braided yarn; 3- Negative electrode fiber material braided yarn; 4- Electropositive fiber material; 5- Electronegative fiber material; 6- Conductive material. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0036] To address the shortcomings of existing technologies, this application provides a multi-level helical braided substrate sensor and its fabrication method. The core of the multi-level helical braided substrate sensor lies in a multi-level composite helical configuration, which exhibits helical characteristics from the inside out and from the macroscopic to the microscopic level, thereby synergistically achieving structural elasticity, sensing, and power generation functions. Specifically, the sensor includes the following components:

[0037] Rigid support material (1): serves as the core skeleton and elastic base of the sensor. It is processed into a helical spring shape, forming the primary helical structure of the sensor. This structure provides the entire sensor with macroscopic elasticity and recoverable deformation capability, enabling it to withstand repeated compression, tension, or bending. Preferably, the rigid support material (1) is a metal wire with good elasticity and conductivity, such as copper wire, stainless steel wire, or spring steel wire, with a diameter of, for example, 0.8-1.0 mm. The diameter of the primary helical structure after winding can be 8-12 mm, and the length can be 10-40 mm.

[0038] Positive electrode fiber material braided yarn (2) and negative electrode fiber material braided yarn (3): These two yarns are the functional carriers of the sensor. They are wrapped around the surface of the rigid support material (1) in a specific way. They are not simply wrapped, but are spirally advanced along the axis of the rigid support material (1) in an alternating (i.e., a section of positive electrode yarn followed by a section of negative electrode yarn) and adjacent (adjacent yarn sections are closely connected but insulated) manner, thereby forming a secondary spiral wrapping functional layer on the skeleton surface.

[0039] The positive electrode fiber material braided yarn (2) is a composite yarn made using a core-spun braiding process. Its outer layer is woven from electropositive fiber material (4). Electropositive fiber material (4) refers to materials that are ranked high in the triboelectric sequence and are prone to losing electrons and becoming positively charged, such as nylon, wool, and silk. Its inner layer (core layer) is composed of conductive material (6), such as silver-plated conductive yarn or copper-nickel composite wire, serving as an electrode for collecting charges.

[0040] The negative electrode fiber material braided yarn (3) is also a core-spun braided structure. Its outer layer is woven from electronegative fiber material (5). Electronegative fiber material (5) refers to materials that are ranked later in the triboelectric sequence, are easy to acquire electrons, and are therefore negatively charged, such as polyimide (PI), polytetrafluoroethylene (PTFE), and polyethylene (PE). Its inner layer (core layer) is also made of conductive material (6), serving as another electrode for collecting charges.

[0041] When the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are wrapped, the same wrapping angle (the angle between the yarn and the skeleton axis, preferably 40°-60°, more preferably 50°) and wrapping interval (the spiral distance between the starting point and the ending point of adjacent yarns of the same type, preferably 20-40 mm, more preferably 31.4 mm) are used. In addition, the number of single wrapping layers and the wrapping density (the number of winding turns within a unit wrapping layer, preferably 5-20 r / layer, more preferably 15 r / layer) are kept consistent to ensure the uniformity of the functional layer and the symmetry of the electrical properties.

[0042] This sensor integrates two working mechanisms: capacitive sensing and triboelectric nanogenerator.

[0043] Capacitive sensing mode: The inner conductive material (6) of the positive electrode fiber material braided yarn (2) and the inner conductive material (6) of the negative electrode fiber material braided yarn (3) serve as two electrodes. The insulating medium between them includes air, and the outer fiber material of both serves as the dielectric layer. When the sensor is subjected to an external force (such as pressure), the primary helical skeleton deforms, causing changes in the distance between the positive and negative electrodes and the effective contact area of ​​the dielectric layer, thereby causing a change in the capacitance value between the two electrodes. By measuring this capacitance change, the magnitude and change of the external force can be sensed with high sensitivity.

[0044] Triboelectric Nanogenerator Mode: When the sensor deforms, contact-separation or relative sliding occurs between the outer layer (electropositive fiber material 4) of the closely adjacent positive electrode fiber material braided yarn (2) and the outer layer (electrone fiber material 5) of the negative electrode fiber material braided yarn (3). According to the triboelectric effect, when in contact, electrons are transferred from the electropositive material to the electronegative material, causing both to carry equal amounts of opposite electrostatic charges; when separated, due to electrostatic induction, a potential difference is generated between the two electrodes, driving electrons to flow in the external circuit, thereby outputting current / voltage and realizing the conversion of mechanical energy into electrical energy.

[0045] This application provides a braided base sensor with a multi-level helical structure, referring to... Figure 1 , Figure 1This is a three-dimensional schematic diagram of the overall structure of a multi-level spiral braided base sensor. The braided base sensor includes: a rigid support material (1), positive electrode fiber material braided yarn (2), and negative electrode fiber material braided yarn (3);

[0046] The rigid support material (1) is wound to form a helical spring-shaped main structure;

[0047] The positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are spirally wrapped around the surface of the rigid support material (1) in an alternating and adjacent manner, forming a spiral wrapping layer together. They are wound into a spiral structure by a winding machine, and after winding, a multi-level spiral structure braided base sensor is formed.

[0048] The positive electrode fiber material braided yarn (2) has a core-spun braided structure, with its outer layer woven from electropositive fiber material (4) and its inner layer composed of conductive material (6);

[0049] The negative electrode fiber material braided yarn (3) has a core-spun braided structure, with its outer layer woven from electronegative fiber material (5) and its inner layer composed of conductive material (6).

[0050] Specifically, in this embodiment, the present application provides a braided base sensor with a multi-level helical structure. For example... Figure 1 As shown, Figure 1 This is a three-dimensional schematic diagram of the overall structure of a multi-level spiral braided base sensor, showing the structure of the corresponding core-spun braided yarn. The braided base sensor mainly includes three core components: a rigid support material (1), a positive electrode fiber material braided yarn (2), and a negative electrode fiber material braided yarn (3).

[0051] The rigid support material (1) is wound into a helical spring-shaped main structure, which serves as the skeleton of the sensor, providing overall structural strength, elasticity, and recoverable deformation capability. This helical spring-shaped design gives the sensor excellent flexibility and three-dimensional adaptability, enabling it to conform well to complex curved surfaces.

[0052] The positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are spirally wound alternately and adjacently on the surface of the rigid support material (1). This means that in the axial direction of the rigid support material, the positive and negative electrode yarns are arranged alternately, adjacent to each other but not overlapping, together forming a uniform spiral-wound functional layer. This linear structure with the functional yarns already wrapped is wound along its own axial direction by a winding machine to form the final spiral structure. After winding, the rigid support material becomes the primary spiral spring skeleton, while the positive and negative electrode yarns alternately wrapped on its surface form the secondary spiral functional layer. The two together constitute the braided base sensor of the "multi-level spiral structure".

[0053] Furthermore, the positive electrode fiber material braided yarn (2) has a unique core-spun braided structure. Its outer layer is woven from electropositive fiber material (4), which is located at the front of the triboelectric sequence (such as nylon or wool) and easily loses electrons and becomes positively charged during friction; its inner layer is composed of conductive material (6) and serves as an electrode for collecting charges. Similarly, the negative electrode fiber material braided yarn (3) also has a core-spun braided structure. Its outer layer is woven from electronegative fiber material (5), which is located at the back of the triboelectric sequence (such as polyimide or polyethylene) and easily gains electrons and becomes negatively charged during friction; its inner layer is also composed of conductive material (6) and serves as another electrode.

[0054] This sensor integrates capacitive sensing and triboelectric nanogenerator mechanisms. When the sensor deforms under external force, on one hand, the two conductive electrodes in the inner layers of the positive and negative yarns, along with the dielectric between them, form a variable capacitor. The capacitance changes with the deformation, thus achieving highly sensitive mechanical sensing (capacitive sensing mode). On the other hand, the deformation causes contact-separation or relative sliding between the outer layers of the positive and negative yarns (electrone materials). Based on triboelectric and electrostatic induction effects, an induced potential difference is generated between the two electrodes, outputting an electrical signal, thereby converting mechanical energy into electrical energy. This integrated dual-mode design allows a single sensor device to simultaneously possess the dual functions of high-precision signal acquisition and efficient energy harvesting.

[0055] The multi-level helical structure transforms a one-dimensional linear functional structure into a three-dimensional helical shape through a winding process, greatly increasing the effective working area and improving performance. Its fabrication method typically includes: first, weaving positive and negative core-spun yarns separately; then, alternately winding them onto a straight, rigid support material according to set parameters; finally, winding the wound yarns into a helical spring shape using a winding machine, thus obtaining the final sensor. This sensor is particularly suitable for smart wearable scenarios requiring flexible fit and self-powered operation, such as integrating it in an array within a bicycle saddle, enabling simultaneous real-time monitoring of riding posture and self-powered lighting / warning using riding vibration energy.

[0056] In one embodiment, the electropositive fiber material (4) is a fibrous material located at a leading position in the triboelectric sequence, including but not limited to at least one of nylon and wool;

[0057] The electronegative fiber material (5) is a fiber material that is ranked low in the triboelectric sequence, including but not limited to at least one of polyimide and polyethylene.

[0058] Specifically, in this embodiment, the electropositive fiber material (4) refers to fibrous materials that rank high in the common triboelectric sequence. A common characteristic of these materials is that their atomic or molecular structure has a relatively weak ability to bind electrons. When they come into contact with and separate from materials ranked lower in the sequence, they more easily lose electrons, thus carrying a net positive charge. In the specific implementation of this application, at least one of the following materials can be used, but is not limited to: nylon (such as nylon 6, nylon 66), wool, etc. For example, nylon is a commonly used choice due to its excellent abrasion resistance and good electropositive properties.

[0059] The electronegative fiber material (5) refers to a fiber material that ranks relatively low in the triboelectric sequence. In contrast to electronegative materials, the atoms or molecules of this type of material have a stronger affinity and binding capacity for electrons. According to the principle of triboelectricity, when they come into contact with the aforementioned electronegative fiber material (4), they more easily steal electrons from it, thereby carrying a net negative charge. In specific implementations of this application, at least one of the following materials may be used, but is not limited to: polyimide, polyethylene, etc. Polyimide is particularly preferred due to its excellent high-temperature resistance, high dielectric strength, and stable strong electronegativity.

[0060] By selecting the aforementioned material pairs with significantly different triboelectric properties, efficient charge transfer can be ensured between the outer layers of the positive and negative electrode yarns during sensor deformation, thus providing a solid foundation for the sensor's triboelectric nanogenerator operating mode.

[0061] In one embodiment, the conductive material (6) is at least one selected from, but not limited to, silver-plated conductive yarn and conductive metal wire.

[0062] Specifically, in this embodiment, the composition and function of the conductive material (6) are described in detail. The conductive material (6) is a key component of the core electrical circuit of the sensor. In the core-sheath structure of the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3), the conductive material (6) is wrapped inside the functional fiber outer layer as the inner core yarn. It does not directly participate in the triboelectric process of the outer layer, but its high conductivity is crucial to the device performance: when the outer layers of the positive and negative electrode yarns generate static charge due to contact separation, the conductive material (6) located in the inner layer can quickly and efficiently collect these induced charges and conduct the charge out as an electrode, thereby forming observable and usable voltage, current, and charge signals in the external circuit, realizing energy output or sensing signal reading.

[0063] In this embodiment, the optional conductive material (6) is at least one selected from silver-plated conductive yarn and conductive metal wire.

[0064] Silver-plated conductive yarn is a widely used textile-based conductive material. It typically uses high-strength synthetic fiber filaments such as nylon and polyester as a base, with a uniform silver layer coated on its surface through chemical plating or electroplating. This material combines the excellent conductivity of metallic silver with the flexibility and weavability of textile yarn, perfectly adapting to weaving processes and withstanding subsequent wrapping, winding, and repeated bending during use. It is an ideal choice for achieving flexible and durable conductive paths.

[0065] Conductive metal wires are another direct and effective option, such as fine-diameter copper or stainless steel wires. Metal wires themselves possess extremely high intrinsic conductivity and mechanical strength. Using such materials not only meets conductivity requirements, but their inherent rigidity can sometimes provide additional structural support for the core-spun yarn. When selecting such wires, it is necessary to comprehensively consider factors such as the diameter matching the weaving process, flexibility (avoiding excessive stiffness that could affect the fabric's feel or cause breakage), and oxidation resistance.

[0066] The selection of the aforementioned materials with high electrical conductivity, suitable mechanical properties, and processing compatibility as conductive materials (6) ensures low loss and high reliability of the charge transfer path inside the sensor, which is the basis for ensuring its triboelectric power generation output efficiency and capacitive sensing signal stability. Depending on the specific application's requirements for flexibility, strength, or cost, a single material or a combination thereof can be selected.

[0067] In one embodiment, the rigid support material (1) is a metal alloy wire, including but not limited to at least one of copper wire and iron wire.

[0068] Specifically, in this embodiment, the rigid support material (1) constituting the core skeleton of the sensor is specifically defined. The rigid support material (1) is a metal alloy wire, including but not limited to at least one of copper wire, iron wire, etc.

[0069] In the multi-level helical braided base sensor, the rigid support material (1) plays multiple key roles. First, it is the carrier of the sensor's macroscopic shape, forming a helical spring-like main structure through a winding process, which provides the necessary structural rigidity and three-dimensional shape stability for the entire device. Second, and more importantly, as an elastic substrate, its yield strength and elastic modulus determine that the sensor can undergo significant and reversible deformation when subjected to external pressure, tension, or bending force, and quickly return to its original shape after the external force is removed. This excellent elastic recovery capability is the physical basis for the sensor to achieve cyclic and stable operation.

[0070] Copper (such as brass and copper) and iron (such as low-carbon steel wire) and their alloys typically possess high strength and moderate toughness, enabling them to withstand repeated deformations during winding and subsequent use without easily undergoing plastic deformation or fracture, ensuring the durability of the sensor. Appropriately heat-treated copper wire, such as annealed copper wire, or specific types of spring steel wire, possess excellent elastic properties, meeting the requirements of sensors as elastic elements for restoring force and fatigue life. Metal wires are easy to precisely wind and form, resulting in uniformly sized and structurally consistent helical structures, which is beneficial for mass production and performance consistency control. Copper wire also has good ductility.

[0071] Therefore, the selection of metal alloy wires such as copper wire and iron wire as rigid support materials (1) is a comprehensive optimization choice from multiple aspects such as structural mechanical properties, process feasibility and long-term reliability. It ensures that the sensor skeleton has core characteristics such as support, elasticity and durability.

[0072] In one embodiment, the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are wrapped around the surface of the rigid support material (1) with the same wrapping angle and wrapping interval, and the wrapping length and wrapping density of the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are the same.

[0073] Specifically, in this embodiment, specific and strict regulations are made regarding the key parameters of the wrapping process of the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) on the surface of the rigid support material (1).

[0074] Specifically, during the preparation process, the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) must be spirally wrapped with the exact same wrapping angle and wrapping interval. The wrapping angle refers to the angle between the yarn's forward direction and the axis of the rigid support material (1), and its magnitude directly affects the tightness of the spiral on the skeleton surface and the deformation mode under stress; the wrapping interval refers to the axial distance between the starting points of adjacent, same type of yarn (such as two adjacent positive electrode yarn segments), which determines the spatial distribution period of the positive and negative electrode functional material segments. The requirement that both parameters be the same ensures the strict symmetry and periodicity of the functional layer in terms of geometry.

[0075] Furthermore, the wrapping length (i.e., the axial length of a single continuous wrapping) and wrapping density (referring to the number of wrapping turns within a single layer of wrapping length) of the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) must also be consistent. The same wrapping length ensures that the positive and negative electrode functional sections have equal proportions in the sensor; the same wrapping density ensures the tightness of the connection between the two and the skeleton in the local area, as well as the consistency of their own structure. This dual consistency in length and density microscopically ensures that the mechanical response characteristics (such as stiffness and deformation) and electrical response characteristics (such as capacitance change baseline and triboelectric charge transfer amount) of the positive electrode region and the negative electrode region are highly matched and comparable during subsequent winding and final deformation.

[0076] A method for fabricating a braided base sensor with a multi-level helical structure, the method comprising the following steps:

[0077] S1: Multiple positively charged fiber yarns are used as the outer layer and a conductive material (6) is used as the inner layer. The positive fiber material braided yarn (2) is formed by braiding with a braiding machine. Multiple negatively charged fiber yarns are used as the outer layer and a conductive material (6) is used as the inner layer. The negative fiber material braided yarn (3) is formed by braiding with the braiding machine.

[0078] S2: The positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are wrapped alternately and adjacently on the surface of a rigid support material (1) at a preset wrapping angle and wrapping interval;

[0079] S3: The rigid support material (1) wrapped with the braided yarn in step S2 is wound into a spiral spring-like structure to obtain the braided base sensor with the multi-level spiral structure.

[0080] Specifically, in this embodiment, the present application describes a method for fabricating a braided base sensor with a multi-level helical structure. Figure 2This diagram illustrates the fabrication process of a braided sensor. Through three precisely linked and parameter-controllable steps, textile weaving, mechanical wrapping, and winding techniques are organically combined to repeatedly and efficiently produce sensors with consistent structure and superior performance. The fabrication method specifically includes the following steps:

[0081] Step S1: Prepare functional composite core-spun braided yarn.

[0082] This step aims to prepare the core functional unit of the sensor—the positive and negative electrode fiber material braided yarn. The specific operation is as follows: First, multiple electropositive fiber yarns (such as nylon yarn with a linear density of 56 tex) are used as the outer layer braiding yarn, and a conductive yarn (such as silver-plated conductive yarn with a linear density of 40 tex) is used as the inner core yarn. Both are fed into a high-speed braiding machine. The spindle speed of the braiding machine is set to 400-600 r / min (preferably 500 r / min). The machine is started so that the outer layer yarns interweave with each other along a specific trajectory and uniformly and densely wrap the central conductive core yarn, thereby forming a structurally strong positive electrode fiber material braided yarn with external function and internal conductivity (2). Using the same equipment and process parameters, only the outer layer yarn is replaced with multiple electronegative fiber yarns (such as polyimide yarn with a linear density of 32 tex), and a structurally symmetrical negative electrode fiber material braided yarn can be obtained (3). This core-shell structure design ensures the continuity and mechanical protection of the conductive electrodes, while fully exposing the functional fibers, laying the foundation for the subsequent triboelectric process.

[0083] Step S2: Construct spiral functional layers by alternately wrapping them around a rigid skeleton.

[0084] This step is crucial for integrating discrete yarn functional units into an ordered functional layer. First, the two rolls of core-spun yarn obtained in step S1 are placed on a yarn-laying device with precisely controllable tension. Next, a straight rigid support material (1) (such as a copper wire with a diameter of 0.9 mm) is taken and fixed axially. Using a precision device with rotation and translation functions (such as a CNC platform), according to preset process parameters, the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are alternately and intermittently spirally wound onto the surface of the rigid support material (1). Key wrapping parameters include: wrapping angle (the angle between the yarn and the axis, set to 50°), wrapping interval (the spiral distance between the start and end points of adjacent spirals of the same type of yarn, set to 31.4 mm), single-layer wrapping length (set to 31.4 mm), and wrapping density (the number of wrapping turns within a single layer, set to 15r / layer). It is crucial to ensure that the two yarn segments are tightly joined end-to-end, without gaps or overlaps, and that all parameters remain strictly consistent throughout the wrapping process of the positive and negative yarns to form a uniform and regular spiral stripe pattern. This step constructs the sensor's secondary spiral functional layer, and its uniformity is core to ensuring the consistent performance of the final product.

[0085] Step S3: Winding and shaping to obtain the final multi-level spiral structure.

[0086] This step gives the sensor its final macroscopic three-dimensional shape and elastic characteristics. The rigid support material (1), which has been precisely wrapped in step S2 and is still in a straight filament state, is carefully transferred to a CNC precision spring winding machine. According to the sensor size required for the application, the target parameters are set in the winding machine, for example: the spring mean diameter (average diameter) is 10 mm, the effective working number of turns is 3.5 turns, and straight sections are reserved at both ends as leads. The winding program is started, and the machine tightly and evenly winds the linear material into a standard cylindrical helical spring. During this process, the surface wrapped yarn functional layer bends and deforms synchronously with the metal skeleton, but due to the inherent flexibility of the core-spun braided structure and the bonding force between the yarn and the skeleton, the functional layer perfectly adapts to the deformation without damage, peeling or arching. After winding is completed, the finished product can be removed to obtain the multi-level helical structure braided base sensor. Its appearance is a miniature helical spring with a diameter of about 10 mm and a free length of about 35 mm, which has a stable composite structure with a primary helical skeleton bearing and a secondary helical functional layer. This method enables the controllable fabrication of complex sensor structures through standardized process steps and precise parameter control, providing a reliable technical path for large-scale production and integrated application in smart wearable devices.

[0087] In one embodiment, the weaving speed of the weaving machine in step S1 is set to 400-600 r / min;

[0088] The linear density of the electropositive fiber material (4) is 30-60 tex, the linear density of the electronegative fiber material (5) is 30-60 tex, and the linear density of the conductive material (6) is 30-40 tex.

[0089] Specifically, in this embodiment, the key process parameters for preparing the core-spun braided yarn in step S1 were optimized and limited. These parameters are fundamental to ensuring that the functional yarn has a uniform structure, stable performance, and is suitable for subsequent processing. The braiding speed of the braiding machine was set to 400-600 r / min. This speed range is crucial for balancing production efficiency and braiding quality. Too low a speed will reduce yield; too high a speed may lead to insufficient interlacing of the outer yarn, loose wrapping, or even damage to the yarn. Within this optimized range, the outer yarn can wrap the conductive core yarn evenly and densely with appropriate tension and trajectory, forming a core-spun yarn with a stable structure and high roundness, providing qualified raw materials for subsequent precision wrapping. The linear density (weight per 1000 meters, unit: tex) of the three constituent yarns was synergistically designed:

[0090] Electropositive fiber materials (4) (such as nylon yarn) have a linear density of 30-60 tex. Yarns in this range ensure sufficient mechanical strength to withstand weaving and subsequent processing, while also providing suitable flexibility and surface area, which is conducive to triboelectric charging.

[0091] Electronegative fiber materials (5) (such as polyimide yarn) have a linear density of 30-60 tex. This linear density allows them to more fully wrap the core yarn in a core-spun structure and provides a more stable frictional contact interface.

[0092] The conductive material (6) (such as silver-plated yarn) has a linear density of 30-40 tex. This specification ensures that the conductive core yarn has sufficient conductive cross-sectional area to achieve low resistance, while its diameter matches that of the outer yarn, allowing it to be completely and uniformly wrapped. These experimentally optimized parameter combinations collectively ensure that the prepared positive and negative core-spun braided yarns have a consistent structure, reliable mechanical properties, and the expected electrical functional basis.

[0093] In one embodiment, the wrapping angle in step S2 is between 40° and 60°, the wrapping interval is 20-40 mm, the coating density is 5-20 r / layer, and the diameter of the spiral spring-shaped structure obtained after winding in step S3 is 8-12 mm and the length is 10-40 mm.

[0094] Specifically, in this embodiment, the key structural parameters in steps S2 and S3 of the preparation method are specifically defined.

[0095] During the alternating wrapping process in step S2, the wrapping angle is limited to between 40° and 60°. This angle range directly affects the helical path length and bonding strength of the functional yarn on the skeleton surface. Too small an angle may increase the risk of axial slippage of the yarn, while too large an angle may weaken the stability of the helical wrapping and affect the effective working area. The wrapping interval is set to 20 mm to 40 mm, which determines the distribution density and periodicity of the positive and negative electrode functional segments along the length of the sensor, and is an important factor in controlling the spatial resolution and electrical response characteristics. The coating density is limited to 5-20 r / layer. This parameter is directly related to the potential contact area between the positive and negative electrode materials per unit length, and is key to affecting the sensitivity to capacitance changes and the amount of triboelectric charge transfer.

[0096] After the winding process in step S3, the diameter of the resulting helical spring-shaped sensor is limited to 8-12 mm, and the length is limited to 10-40 mm. This size range is an optimal choice considering several factors: firstly, it ensures that the sensor has sufficient mechanical compliance and deformation range to adapt to curved surfaces and dynamic deformations in wearable applications; secondly, this size facilitates high-density integration in a limited space (such as a bicycle saddle); and thirdly, sensors within this range exhibit a good balance between performance output and structural stability in experiments. These precisely defined parameters together constitute an important technological guarantee for realizing the high-performance, multi-stage integrable helical sensor described in this application.

[0097] This application provides a braided base sensor with a multi-level spiral structure, and the specific manufacturing steps are as follows:

[0098] Step S1: In this embodiment, nylon fiber is preferably used as the positive electrode fiber material, polyimide fiber as the negative electrode fiber material, and silver-plated conductive yarn as the conductive material. Sixteen nylon yarns are assembled on the braiding spindle of a high-speed braiding machine. The silver-plated conductive yarn is drawn out from inside the braiding machine by a separate yarn guide device. The 16 nylon yarns are used as the outer layer, and the silver-plated conductive yarn is used as the inner layer, which are then braided into a nylon core-spun braided yarn. Similarly, 16 polyimide yarns are used as the outer layer, and the silver-plated conductive yarn is used as the inner layer, which are then braided into a polyimide core-spun braided yarn.

[0099] The polyimide yarn is 32 tex, the nylon yarn is 56 tex, the silver-plated conductive yarn is 40 tex, and the braiding machine speed is 500 r / min.

[0100] Step S2: After the polyimide core-spun braided yarn and nylon core-spun braided yarn are wound onto two spindles respectively, they are placed on a translation table. The polyimide core-spun braided yarn and nylon core-spun braided yarn are alternately wrapped onto the surface of the copper wire with the same wrapping angle and wrapping interval through a rotation-translation device. The nylon core-spun yarn and polyimide core-spun yarn are wrapped adjacent to each other, and the wrapping length and wrapping density are the same.

[0101] The wrapping angle is 50°, the wrapping interval is 31.4 mm, the single-layer wrapping length is 31.4 mm, and the wrapping density is 15 r / layer.

[0102] Step S3: The above-wound copper wire is wound by a spring winding machine to form a multi-level spiral structure, with polyimide core-spun braided yarn and nylon core-spun braided yarn distributed adjacent to each other;

[0103] The multi-stage spiral structure is formed by winding copper wire with a diameter of 0.9 mm through a spring winding machine, resulting in a diameter of 10 mm and a length of 35 mm.

[0104] By changing the total wrapping length of the polyimide core-spun braided yarn and nylon core-spun braided yarn in step S2 of the preparation method, while keeping the wrapping angle and wrapping interval constant (and thus the wrapping density constant), multi-level helical braided base sensors with different wrapping lengths were obtained. The total wrapping lengths were 62.8 mm, 125.6 mm, 251.2 mm, and 502.4 mm, respectively, meaning that the effective number of turns of the polyimide core-spun braided yarn and nylon core-spun braided yarn participating in relative motion were 1, 2, 3, and 4 turns, respectively.

[0105] The multi-level helical braided base sensors with different wrapping lengths were subjected to capacitive sensing performance and electrical output performance tests. When the wrapping length was 502.4 mm, i.e., the effective number of turns of the polyimide core-spun braided yarn and the nylon core-spun braided yarn participating in the relative motion were 4 turns respectively, the multi-level helical braided base sensor exhibited the best capacitive sensing performance and electrical output performance.

[0106] The test method for capacitive sensing performance is as follows:

[0107] A multi-level spiral braided base sensor is fixed on a flexible electronic testing platform. As the slide moves back and forth, the multi-level spiral braided base sensor is intermittently pressed. The silver-plated conductive yarns inside the nylon core-spun braided yarn and the polyimide core-spun braided yarn are respectively connected to the positive and negative terminals of the TruEbox02CM capacitive data acquisition system to measure the capacitive sensing performance of the multi-level spiral braided base sensor.

[0108] The test method for triboelectric output performance is as follows:

[0109] A multi-stage spiral braided base sensor is fixed on a triboelectric power generation mechanism. As the connecting rod reciprocates, it intermittently presses the multi-stage spiral braided base sensor. The silver-plated conductive yarns inside the nylon core-spun braided yarn and the polyimide core-spun braided yarn are respectively connected to a Keithley 6514 electrometer to measure the triboelectric output performance of the multi-stage spiral braided base sensor.

[0110] Figure 3 a and 3b are the sensitivity dot plot and output voltage curve of the multi-level helical braided base sensor obtained in the embodiments of this application, where D1, D2, D3, and D4 are 7 r / layer, 9 r / layer, 11 r / layer, and 15 r / layer, respectively; as shown in Figure 3b. Figure 3 As shown in a and 3b, the capacitive sensing performance and electrical output performance of the braided base sensor with a multi-level helical structure are optimal when the wrapping density is D4.

[0111] Figure 4 a and 4b are the sensitivity dot plot and output voltage curve of the braided base sensor with a multi-level helical structure obtained in the embodiments of this application; as shown... Figure 4 As shown in a and 4b, when the wrapping length is 502.4 mm, that is, when the effective number of turns of the polyimide core-spun braided yarn and the nylon core-spun braided yarn participating in the relative motion are 4 turns respectively, the multi-level spiral structure braided base sensor has the best capacitive sensing performance and electrical output performance.

[0112] The application of a multi-level helical structure braided base sensor in bicycle motion monitoring and self-powered lighting includes:

[0113] Multiple braided base sensors are integrated in an array inside the bicycle saddle to form a distributed intelligent pressure sensing system.

[0114] The woven base sensor is used to monitor the distribution and dynamic changes of seat pressure during cycling in real time to detect and evaluate cycling posture; and / or to collect the mechanical energy generated in the saddle during cycling and convert it into electrical energy to power the bicycle lighting system.

[0115] Specifically, in this embodiment, multiple woven-based sensors prepared according to this application are arranged in a pre-designed matrix or specific pattern and integrated and encapsulated inside the flexible padding (such as foam or gel layer) of a bicycle saddle. These sensor units constitute a distributed, embedded intelligent pressure sensing network within the saddle. Each sensor, as an independent sensing and micro-energy harvesting node, has a helical spring-like structure that can adapt well to the irregular space inside the saddle and achieve dynamic conformal fit with the curvature of the human buttocks.

[0116] During cycling, different rider postures (such as normal sitting posture, leaning forward to accelerate, leaning back to decelerate, and leaning left or right to turn) cause characteristic spatiotemporal changes in the contact pressure distribution between the buttocks and the saddle. An integrated sensor array within the saddle, through its capacitive sensing mode, can detect pressure changes at localized locations in real time with high sensitivity. The capacitive signals from all sensors are synchronously collected and transmitted to a processing unit (such as a microcontroller), where algorithms reconstruct a dynamic pressure distribution map of the entire saddle surface. Further analysis of this pressure distribution using pattern recognition or machine learning algorithms allows for accurate real-time identification of the current cycling posture (e.g., left turn preparation, right turn preparation, standing up and rocking, emergency braking, etc.), and can provide early warnings for poor posture, offering quantitative data for improving cycling efficiency, optimizing posture, and preventing sports injuries.

[0117] During cycling, road bumps, bike vibrations, and the rider's own dynamic movements (such as pedaling and standing up) continuously subject the saddle to intermittent mechanical shocks and pressure changes. At this time, the sensor array operates synchronously in triboelectric nanogenerator mode, efficiently converting the dissipated mechanical energy into pulsed electrical energy. Through parallel / series connections and efficient power management circuitry (including rectification, filtering, and energy storage components such as supercapacitors), the dispersed electrical energy can be collected and stored. The accumulated electrical energy can be directly used to power low-power bicycle lighting systems, such as smart taillights.

[0118] More importantly, the system enables an intelligent closed loop of perception and execution. For example, when the system identifies a cyclist's intention to turn left by analyzing pressure distribution, it can automatically control the intelligent taillight, powered by its own collected electricity, to switch to a left turn indicator flashing mode. Similarly, upon detecting a braking posture, it can trigger the high-mounted brake light to illuminate or flash at high frequency. This significantly improves the active safety of bicycles at night or in low-visibility environments, and eliminates the need for external batteries, achieving true energy autonomy and functional intelligence.

[0119] The above description is merely a preferred embodiment of this application and is not intended to limit this application. For those skilled in the art, various modifications and alterations can be made to this application without departing from the spirit and scope thereof, and such modifications and alterations are also considered to fall within the protection scope of this application as defined by the appended claims. For example, the rigid support material is not limited to copper wire, but can also be other elastic metal wires or high-performance polymer monofilaments; the positive and negative electrode fiber materials can be selected from other types according to the triboelectric sequence and actual needs; the sensor size and helical parameters can be flexibly adjusted according to specific application scenarios (such as wearable devices in different parts of the body); the array arrangement and data processing algorithm can be more complex and intelligent.

[0120] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0121] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A braided base sensor with a multi-stage helical structure, characterized in that, The braided base sensor includes: a rigid support material (1), a positive electrode fiber material braided yarn (2), and a negative electrode fiber material braided yarn (3). The rigid support material (1) is wound to form a helical spring-shaped main structure; The positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are spirally wrapped around the surface of the rigid support material (1) in an alternating and adjacent manner, forming a spiral wrapping layer together. They are wound into a spiral structure by a winding machine, and after winding, a multi-level spiral structure braided base sensor is formed. The positive electrode fiber material braided yarn (2) has a core-spun braided structure, with its outer layer woven from electropositive fiber material (4) and its inner layer composed of conductive material (6); The negative electrode fiber material braided yarn (3) has a core-spun braided structure, with its outer layer woven from electronegative fiber material (5) and its inner layer composed of conductive material (6).

2. The braided base sensor with a multi-stage helical structure according to claim 1, characterized in that, The electropositive fiber material (4) is a fibrous material that is located at a forward position in the triboelectric sequence, including but not limited to at least one of nylon and wool; The electronegative fiber material (5) is a fiber material that is ranked low in the triboelectric sequence, including but not limited to at least one of polyimide and polyethylene.

3. The braided base sensor with a multi-stage helical structure according to claim 1, characterized in that, The conductive material (6) is selected from at least one of the following: including but not limited to silver-plated conductive yarn and conductive metal wire.

4. The braided base sensor with a multi-stage helical structure according to claim 1, characterized in that, The rigid support material (1) is a metal alloy wire, including but not limited to at least one of copper wire and iron wire.

5. The braided base sensor with a multi-stage helical structure according to claim 1, characterized in that, The positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are wrapped around the surface of the rigid support material (1) at a preset wrapping angle and wrapping interval, and the wrapping length and wrapping density of the positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are the same.

6. A method for preparing a braided base sensor with a multi-level helical structure according to any one of claims 1-5, characterized in that, The method includes the following steps: S1: Multiple positively charged fiber yarns are used as the outer layer and a conductive material (6) is used as the inner layer. The positive fiber material braided yarn (2) is formed by braiding with a braiding machine. Multiple negatively charged fiber yarns are used as the outer layer and a conductive material (6) is used as the inner layer. The negative fiber material braided yarn (3) is formed by braiding with the braiding machine. S2: The positive electrode fiber material braided yarn (2) and the negative electrode fiber material braided yarn (3) are wrapped alternately and adjacently on the surface of a rigid support material (1) at a preset wrapping angle and wrapping interval; S3: The rigid support material (1) wrapped with the braided yarn in step S2 is wound into a spiral spring-like structure to obtain the braided base sensor with the multi-level spiral structure.

7. The preparation method according to claim 6, characterized in that, The weaving speed of the braiding machine in step S1 is set to 400-600 r / min; the linear density of the electropositive fiber material (4) is 30-60 tex, the linear density of the electronegative fiber material (5) is 30-60 tex, and the linear density of the conductive material (6) is 30-40 tex.

8. The preparation method according to claim 6, characterized in that, The wrapping angle in step S2 is between 40° and 60°, and the wrapping interval is 20-40 mm; the coating density is 5-20 r / layer; the diameter of the spiral spring-shaped structure obtained after winding in step S3 is 8-12 mm, and the length is 10-40 mm.

9. The application of a braided base sensor with a multi-stage spiral structure as described in any one of claims 1-6 in bicycle motion monitoring and self-powered lighting, characterized in that, include: Multiple braided base sensors are integrated in an array inside the bicycle saddle to form a distributed intelligent pressure sensing system. The braided base sensor is used to monitor the distribution and dynamic changes of seated pressure during cycling in real time, in order to detect and evaluate cycling posture. And / or, collect the mechanical energy generated in the saddle during riding and convert it into electrical energy to power the bicycle lighting system.

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