A low-power electromagnetic resonant tactile exciter, its design method, and a wearable device.

Abstract

A low-power electromagnetic resonant tactile exciter, its design method, and a wearable device are disclosed, belonging to the field of tactile feedback technology. In the exciter: a slit is formed in the middle of a thin-film attachment layer, dividing it into an inner disk and an outer annular band, connected by a fan-shaped cantilever beam; the fixed end of the fan-shaped cantilever beam is fixedly connected to a drive coil layer, and the free end is fixedly connected to a magnet, with a preset central angle to adjust the resonant frequency. The drive coil layer is an annular cylinder made of wound copper wire, surrounding the magnet; an anti-fall-off bottom cover layer is located at the bottom of the drive coil layer. This invention achieves a low-power design for the electromagnetic resonant tactile exciter through multi-parameter collaborative optimization, enabling precise control of the resonant frequency of the tactile exciter to match the sensitive frequency band of the skin; the operating power consumption is only in the microwatt range, and it is integrated into a soft, thin electronic skin through an extendable serpentine connecting line and a perforated, breathable flexible substrate, significantly reducing energy consumption while significantly improving user comfort.

Description

Technical Field

[0001] This invention belongs to the field of haptic feedback technology, and relates to a low-power electromagnetic resonant haptic exciter, its design method, and a wearable device. Background Technology

[0002] A haptic exciter is an electronic device that provides tactile stimulation to the user's skin surface, achieving a high-fidelity reproduction of tactile sensations by simulating real external stimuli. In applications such as human-computer interaction, virtual reality, and augmented reality, low-power, miniaturized, low-latency, and high-resolution haptic exciters play a crucial role in enhancing immersion and operational accuracy. Existing solutions have not yet met all these requirements. For example, Chinese invention patent CN115509343A proposes applying an alternating electric field to a feedback arm to drive a magnetic vibration component. It uses a design where the magnet floats above the electromagnetic coil, but does not provide corresponding design theory or methods, and the unit power consumption is as high as tens of milliwatts or more. In addition, because it uses silicone potting and encapsulation, the integrated device is relatively thick and cannot work stably on highly curved surfaces such as human joints. The haptic actuator and wearable haptic skin disclosed in Chinese invention patent CN117251047A lack power consumption optimization design, resulting in high driving power consumption (exceeding 100 mW), which makes it difficult to meet the requirements of long-term wear and array integration. Furthermore, due to the lack of a stretchable serpentine wiring structure, its stretch compliance and skin fit are limited, and its ability to operate stably on complex curved surfaces such as joint recesses and protrusions is insufficient. These limitations further restrict the practical application scenarios of the haptic actuator and its integrated wearable devices, as well as the user experience.

[0003] Therefore, it is necessary to develop a design methodology for low-power haptic feedback devices, ensuring high flexibility after integration, enabling close and conformal adhesion to human skin, effective mechanical tactile stimulation within the skin's high-sensitivity frequency range, stable operation under conditions of large deformation and complex curved surfaces, and support for multi-point arraying and low-power driving to meet the needs of full-body wearable systems. This technology will provide crucial support for building lightweight, long-lasting, and highly comfortable immersive haptic interaction systems in the future, and will also become a core foundation for advancing the development of wireless smart skin and flexible human-machine interfaces. Summary of the Invention

[0004] To address the problems of existing technologies, this invention proposes a low-power electromagnetic resonant tactile exciter, its design method, and a wearable device. This device can output significant mechanical vibration stimulation with microwatt-level power consumption, providing users with clear tactile stimulation while maintaining excellent skin-friendly softness and mechanical reliability. It solves the problems of high power consumption, large size, and poor flexibility of existing electromagnetic resonant tactile exciters, thereby enabling its wireless operation and large-area integration on the human body surface.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A low-power electromagnetic resonant tactile actuator, comprising, from top to bottom, the following layers stacked sequentially: a thin film adhesion layer, a magnet, a drive coil layer, and an anti-detachment bottom cover layer; specifically:

[0007] The thin film adhesion layer has a sheet-like structure with a circumferentially continuous slit in its center, dividing the film adhesion layer into a free end and a fixed end. The slit is a C-shaped arc segment, meaning it is not connected circumferentially, forming a fan-shaped cantilever beam. The free end and the fixed end are connected by this fan-shaped cantilever beam, forming an integrated structure. The bottom of the fixed end is bonded to the top of the drive coil layer, and the bottom of the free end is bonded to the upper surface of the magnet. The top of the free end serves as the working surface in contact with the target object, thereby effectively transmitting the magnet's vibration to the target object.

[0008] The driving coil layer is a ring-shaped cylinder with a certain thickness, which is tightly wound with copper wire and placed around the magnet. The inner cavity of the ring-shaped cylinder forms a space for the magnet to move. The magnet is located entirely or partially in the inner cavity of the ring-shaped cylinder, and the size of the inner cavity of the ring-shaped cylinder is larger than the size of the magnet.

[0009] The anti-detachment bottom cover layer covers and adheres to the bottom of the drive coil layer to prevent the magnet from accidentally detaching during vibration.

[0010] Furthermore, the drive coil layer is arranged coaxially with the magnet.

[0011] Furthermore, the film attachment layer is a flexible insulating film, including polyimide, polyethylene terephthalate, polymethyl methacrylate, and polypropylene, preferably polyimide; the anti-detachment bottom cover layer is made of a flexible insulating film material.

[0012] Furthermore, the magnet is a high-performance miniature permanent magnet; its central axis is the magnetization direction, and the central axis of the magnet is coaxial with the central axis of the driving coil layer; an alternating current is passed through the driving coil layer to generate an alternating electromagnetic field, which drives the magnet to reciprocate under the action of electromagnetic force, and the magnet does not collide with the surrounding structure during the vibration process.

[0013] Furthermore, the sector-shaped cantilever beam of the electromagnetic resonant tactile exciter has a preset central angle to adjust its resonant frequency, specifically:

[0014] The inner arc surface of the fan-shaped cantilever beam is connected to the free end, and the outer arc surface is connected to the fixed end. The left and right sides are straight segments, and the extension lines of the two straight segments form a central angle with the center of the film attachment layer. The central angle is an important structural design parameter used to control the resonant frequency of the tactile exciter.

[0015] A design method for a low-power electromagnetic resonant tactile exciter is disclosed. This method involves multi-parameter collaborative optimization of the geometry and relative position of the drive coil layer and magnet to maximize the electromagnetic force output of the tactile exciter while maintaining a constant power consumption, thereby achieving a low-power design. The method also involves adjusting the geometric parameters of the drive coil layer and magnet, as well as the preset central angle of the fan-shaped cantilever beam, to precisely match the resonant frequency of the electromagnetic resonant tactile exciter to the sensitive frequency band. The method includes the following steps:

[0016] S1, Establish a coil-magnet axisymmetric model to maximize the normalized electromagnetic force of the electromagnetic resonant tactile exciter, thereby achieving its low-power design: Calculate the normalized electromagnetic force using formula (1):

[0017] (1)

[0018] In the formula, It is normalized electromagnetic force; F The electromagnetic force applied to the magnet is generated by the driving coil layer; μ 0 is the permeability of free space; M It is the saturation magnetization of the magnet; P It is the power consumed by the electromagnetic resonant tactile exciter; ρ It is the resistivity of the wire wound into the drive coil; V magnet It is the volume of the magnet; f The resonant frequency of the electromagnetic resonant haptic exciter, relative to the height of the magnet. H magnet The radius of the magnet R magnet Height of the driving coil layer H coil Outer radius of the driving coil layer R outer Inner radius of the driving coil layer The distance between the geometric center of the magnet and the geometric center of the driving coil layer is z 0 related.

[0019] The dimensionless design parameter combination that maximizes the normalized electromagnetic force of the electromagnetic resonant tactile exciter is determined by the above formula.

[0020] S2, Establish a theoretical model for precisely controlling the resonant frequency of the electromagnetic resonant tactile exciter:

[0021] The mass of the magnet-sector cantilever beam dynamic system is equal to the mass of the magnet, expressed as: ,in ρ magnet The density of the magnet, R magnetLet be the radius of the magnet. H magnet The thickness of the magnet;

[0022] Furthermore, the system stiffness of the magnet-sector cantilever beam dynamic system depends on the material parameters of the sector cantilever beam, and the resonant frequency of the electromagnetic resonant tactile exciter is expressed as:

[0023] (2)

[0024] in, E PI Young's modulus of the material for the fan-shaped cantilever beam; H PI The thickness of the fan-shaped cantilever beam; θ The central angle of the fan-shaped cantilever beam; R magnet Let be the radius of the magnet; ρ magnet It is the density of the magnet; R inner The inner radius of the driving coil layer; For about θ The fitting expression, preferably in the form of... ; For about θ The fitting expression, preferably in the form of... ;

[0025] The E PI For material parameters, the R magnet , H PI , R inner , θ For geometric parameters. According to formula (2), by adjusting the material parameters and geometric parameters in the theoretical model, the resonant frequency of the electromagnetic resonant tactile exciter can be precisely controlled, thereby maximizing the electromagnetic force output of the electromagnetic resonant tactile exciter.

[0026] Furthermore, the synergistic optimization design of S1 and S2 enables the electromagnetic resonant tactile exciter to generate sufficiently significant tactile stimulation on the target contact object with low power consumption.

[0027] A wearable device utilizes the aforementioned low-power electromagnetic resonant tactile actuators integrated into a thin, flexible electronic skin. The thin electronic skin consists of an array of these low-power electromagnetic resonant tactile actuators arranged on a pre-perforated silicone elastic substrate. Adjacent low-power electromagnetic resonant tactile actuators are interconnected via serpentine connecting lines of a metal-flexible insulating film-metal composite layer. In use, an alternating current is applied to the drive coil layer to generate an alternating magnetic field, driving a magnet to reciprocate. Pressure and vibration signals are transmitted to the target object via a fan-shaped cantilever beam. The wearable device exhibits excellent stretchability, maintaining the continuity of circuit connections and the stability of control signal transmission even under various complex large deformations (such as 60% uniaxial stretching, a bending radius of 12 mm, and 90° torsion). Specifically:

[0028] The metal-flexible insulating film-metal composite layer comprises an upper metal conductive layer, a flexible insulating film, and a lower metal conductive layer. It is integrally formed with the film attachment layer using a laser cutting process. A serpentine interconnecting wire is fabricated radially outward from the film attachment layer, achieving structural integration and enabling circuit connections between tactile exciters. The serpentine interconnecting wire is extensible; when the device deforms with the substrate, its structure can adapt to external deformation through its own elastic deformation, reducing constraint on the film attachment layer and minimizing local stress concentration. The silicone elastic substrate uses a flexible silicone film structure to provide mechanical support and fixation for the serpentine connecting wires of the metal-flexible insulating film-metal composite layer and the low-power electromagnetic resonant tactile exciter. It also achieves a smooth and conformal adhesion between the entire device and the surface of the target contact object, such as human skin. Several through-holes in the silicone elastic substrate allow air circulation between the substrate and the target contact object, reducing stuffiness and dampness during prolonged wear. The silicone material itself has good softness and elasticity, preventing localized pressure and further improving wearing comfort.

[0029] The target contact object can be human skin or other objects that require tactile stimulation.

[0030] Furthermore, in the metal-flexible insulating film-metal composite layer, the materials of the upper and lower metal conductive layers can be the same or different, and the metals include copper, gold, and silver, with copper being preferred; the materials of the flexible insulating film include polyimide, polyethylene terephthalate, polymethyl methacrylate, and polypropylene, with polyimide being preferred.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The tactile exciter proposed in this invention adopts low-power geometry optimization and resonance enhancement design, which can achieve microwatt-level power consumption drive.

[0033] (2) This invention is applicable to large-area, distributed, wireless haptic feedback systems and has good scalability and deployment flexibility.

[0034] (3) The present invention integrates a tactile exciter array and a serpentine connecting line on a silicone elastic substrate to achieve an integrated design with excellent human body adaptability. It is especially suitable for long-term skin contact and conformal adhesion to complex curved areas of the human body, thereby improving the interactive immersion and energy efficiency of wearable devices.

[0035] (4) This invention supports array integration, which can maintain the continuity of electrical connection and the stability of control signal transmission under various complex deformations. It can be widely used in various tactile feedback scenarios such as Braille recognition, directional navigation, and immersive VR / AR.

[0036] (5) This invention provides a complete low-power, highly compatible solution for wearable haptic feedback systems that can be applied over a large area of ​​the whole body. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall structure of a low-power electromagnetic resonant tactile exciter according to an embodiment of the present invention;

[0038] Figure 2 This is an exploded view of the structure of a low-power electromagnetic resonant tactile exciter according to an embodiment of the present invention;

[0039] Figure 3 This is the analytical model and electromagnetic force optimization results of the low-power design of the electromagnetic resonant tactile exciter of this invention; Figure 3 (a) in the figure is the analysis model used for low power design; Figure 3 (b) in the figure represents the ratio of the center distance between the drive coil and the magnet to the coil height. z 0 / H coil The relationship between normalized electromagnetic forces; Figure 3 In the equation (c), the ratio of the inner radius to the outer radius of the driving coil is given. R inner / R outer The relationship between normalized electromagnetic forces; Figure 3 In this context, (d) represents the ratio of the magnet's radius to its height. R magnet / H magnet The relationship between normalized electromagnetic forces; Figure 3 In this context, (e) represents the ratio of the magnet height to the drive coil height. H magnet / H coil The relationship between normalized electromagnetic forces; Figure 3In this context, (f) represents the ratio of the magnet radius to the inner radius of the drive coil. R magnet / R inner The relationship between normalized electromagnetic forces;

[0040] Figure 4 This is a schematic diagram of a model for the theory of precisely controlling the resonant frequency of an electromagnetic resonant tactile exciter; Figure 4 (a) in the figure is a model cross-section diagram used for theoretical analysis of precise control of the resonant frequency of electromagnetic resonant tactile exciter; Figure 4 (b) is a top view of the model used for theoretical analysis of precise control of the resonant frequency of an electromagnetic resonant tactile exciter;

[0041] Figure 5 It is the result of calculation based on the theory of precisely controlling the resonant frequency of the electromagnetic resonant tactile exciter; Figure 5 In the figure, (a) represents the normalized frequency and the dimensionless parameter. H PI / R inner ) 1.5 The linear relationship between them; Figure 5 In the equation (b), the normalized frequency and dimensionless parameter are ( R magnet / R inner ) 1.5 The relationship curve between the two curves; Figure 5 (c) in the theoretical model refers to the information about... θ Fitting expression and ;

[0042] Figure 6 This is the curve showing the relationship between the vibration amplitude of the magnet and the current frequency of the electromagnetic resonant tactile exciter of the present invention under a 5mA sinusoidal current input.

[0043] Figure 7 This is a graph showing the relationship between input power and vibration amplitude at the resonant frequency of the electromagnetic resonant tactile exciter of the present invention.

[0044] Figure 8 This is a schematic diagram of a thin, soft electronic skin integrating nine independent electromagnetic resonant tactile exciters; Figure 8 (a) in the figure is an exploded view of a soft, thin electronic skin; Figure 8 (b) is a schematic diagram of the geometric structure of the metal-flexible insulating film-metal composite layer; Figure 8 (c) in the diagram is an exploded view of the electromagnetic resonant tactile exciter; Figure 8 (d) in the diagram is a functional schematic of the silicone elastic substrate;

[0045] Figure 9 This is a frequency sweep experiment that uses the proposed exciter to evaluate the power consumption of tactile perception threshold in subjects of different genders;

[0046] Figure 10 The results are experimental findings of measuring the tactile perception threshold power consumption of subjects in different age groups at a frequency of 200 Hz using the proposed exciter.

[0047] Figure 11 These are experimental results of using the soft, thin electronic skin of this invention, installed on the back of the user's hand, to display Braille characters; Figure 11 (a) in the image is a static pattern of the electromagnetic resonant tactile exciter used in the experiment to display Braille characters; Figure 11 (b) in the figure represents the experimental results reflecting the actual pattern and the predicted pattern;

[0048] Figure 12 These are the experimental results of using the soft, thin electronic skin of this invention to provide directional tactile feedback; Figure 12 (a) in the image is a dynamic pattern of an electromagnetic resonant tactile exciter that provides directional tactile feedback, which cycles every 3 seconds. Figure 12 (b) represents the accuracy of the device in guiding direction in the hand, arm, chest, and back.

[0049] In the figure: 1 Low-power electromagnetic resonant tactile actuator; 2 Thin film adhesion layer; 3 Magnet; 4 Drive coil layer; 5 Anti-fall-off bottom cover layer; 6 Fan-shaped cantilever beam; 7 Metal-flexible insulating film-metal composite layer; 8 Silicone elastic substrate; 9 Target contact object. Detailed Implementation

[0050] To fully illustrate the specific embodiments of the present invention, further detailed descriptions are provided below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0051] This invention provides a low-power electromagnetic resonant tactile exciter that can output significant mechanical vibration stimulation with microwatt-level power consumption, providing users with clear tactile feedback.

[0052] Specifically, such as Figure 1 As shown, the present invention provides a low-power electromagnetic resonant tactile exciter 1, the exploded view of which is shown below. Figure 2 As shown, it includes a thin film adhesion layer 2, a magnet 3, a drive coil layer 4, and an anti-detachment bottom cover layer 5, which are stacked from top to bottom.

[0053] The thin film adhesion layer 2 has a disc-shaped structure with a circumferentially continuous slit in its center, dividing it into an inner disc and an outer annular band. The slit is a C-shaped arc segment, meaning it is not connected, forming a fan-shaped cantilever beam 6. The inner disc and the outer annular band are connected by the fan-shaped cantilever beam 6, forming an integrated structure. The end of the fan-shaped cantilever beam 6 near the inner disc is a free end, and the end near the outer annular band is a fixed end. The bottom of the fixed end of the fan-shaped cantilever beam 6 in the thin film adhesion layer 2 is bonded to the top of the drive coil layer 4, and the bottom of its free end is bonded to the top of the magnet 3. The thin film adhesion layer 2 is a flexible insulating film, and its materials include polyimide, polyethylene terephthalate, polymethyl methacrylate, and polypropylene. In this embodiment, polyimide is used, and its thickness is 24 μm. The geometric structure of the fan-shaped cantilever beam 6 is fan-shaped at the fixed end and narrows at the free end to allow for the adhesion and support of the magnet 3; its central angle is selected in the range of 0° to 360° to adjust the resonant frequency of the system; for example, when the central angle is 60°, with a magnet 3 of a certain mass attached, the resonant frequency of the tactile exciter can be adjusted to around 200Hz.

[0054] The magnet 3 is a high-performance miniature permanent magnet (neodymium iron boron rare earth permanent magnet is used in this embodiment), and its shape is a thin sheet (a thin disc is used in this embodiment). Its size and mass are designed and selected according to the target frequency and actual application requirements. The magnet 3 is fixed to the free end of the fan-shaped cantilever beam 6 with biocompatible adhesive. The central axis of the magnet 3 is in its magnetization direction, and the central axis of the magnet is coaxial with the central axis of the drive coil layer 4. An alternating current is passed through the drive coil layer 4 to generate an alternating electromagnetic field, driving the magnet 3 to reciprocate under the action of electromagnetic force. The magnet 3 does not collide with the surrounding structure during vibration. The mass of the magnet 3 is matched with the parameters of the fan-shaped cantilever beam to adjust the system resonant frequency to the desired value.

[0055] The drive coil layer 4 is a tightly wound annular cylinder of a certain thickness, surrounded by copper wire, and is a multi-turn spiral coil wound with conductive metal microwires (such as enameled copper wire). The inner cavity of the annular cylinder forms the space for the magnet to move, and the magnet is located in the inner cavity of the annular cylinder, with the inner cavity size larger than the magnet 3. Through multi-parameter optimization design, when the drive coil layer 4 has only tens of microwatts of power input, it can still generate a significant driving electromagnetic force on the magnet 3. The two ends of the drive coil layer 4 are connected to the external drive circuit through patterned serpentine connecting lines to ensure the reliability of electrical connection under skin adhesion and bending conditions.

[0056] The anti-detachment bottom cover layer 5 covers and adheres to the bottom of the drive coil layer 4 as part of the encapsulation structure. It is used to prevent the magnet 3 from accidentally detaching during vibration, while also preventing external contaminants such as dust from entering. It is made of a flexible insulating film material (such as polyimide film or silicone rubber elastomer; in this embodiment, polyimide film is selected).

[0057] Furthermore, the outer diameter of the fan-shaped cantilever beam 6 coincides with the inner diameter of the drive coil layer 4.

[0058] This embodiment provides a design method for a low-power electromagnetic resonant tactile exciter, including the following steps:

[0059] S1. Establish a coil-magnet axisymmetric model to maximize the normalized electromagnetic force of the electromagnetic resonant haptic actuator, thereby achieving a low-power design for the haptic actuator:

[0060] The target contact object 9 can be human skin or other objects that require tactile stimulation. Tactile perception in the skin primarily relies on various mechanoreceptors under the skin, particularly Meissner's corpuscles and Pacinian corpuscles, which have low activation thresholds and rapid adaptation characteristics, making them especially sensitive to external vibration stimuli in the 100Hz to 300Hz frequency range. Therefore, designing tactile exciters that operate within this frequency band is crucial for achieving high-performance tactile feedback. Figure 3 The electromagnetic force analysis model and optimization results of the electromagnetic resonant tactile exciter of this invention are presented. Figure 3 (a) in the figure is an analysis model used for low-power design. Figure 3 (b) in the figure represents the ratio of the center distance between the drive coil and the magnet to the coil height. z 0 / H coil The relationship between normalized electromagnetic forces Figure 3 In the equation (c), the ratio of the inner radius to the outer radius of the driving coil is given. R inner / R outer The relationship between normalized electromagnetic forces Figure 3 In this context, (d) represents the ratio of the magnet's radius to its height. R magnet / H magnet The relationship between normalized electromagnetic forces Figure 3 In this context, (e) represents the ratio of the magnet height to the drive coil height. H magnet / H coil The relationship between normalized electromagnetic forces Figure 3 In this context, (f) represents the ratio of the magnet radius to the inner radius of the drive coil. R magnet / R inner The relationship between the normalized electromagnetic force and the electromagnetic force analysis model comprehensively considers the geometric parameters, material properties, and internal component assembly and positioning of the electromagnetic resonant haptic exciter, and is used to independently evaluate the influence of each parameter. The normalized electromagnetic force is calculated and verified by finite element analysis. The normalized electromagnetic force calculation formula is established as shown in formula (1):

[0061] (1)

[0062] In the formula, It is normalized electromagnetic force; F The electromagnetic force applied to the magnet is generated by the driving coil layer; μ 0 is the permeability of free space; M It is the saturation magnetization of the magnet; P It is the power consumed by the electromagnetic resonant tactile exciter; ρ It is the resistivity of the wire wound into the drive coil; V magnet It is the volume of the magnet; f The resonant frequency of the electromagnetic resonant haptic exciter, relative to the height of the magnet. H magnet The radius of the magnet R magnet Height of the driving coil layer H coil Outer radius of the driving coil layer R outer Inner radius of the driving coil layer The distance between the geometric center of the magnet and the geometric center of the driving coil layer is z 0 related.

[0063] The dimensionless design parameter combination that maximizes the normalized electromagnetic force of the electromagnetic resonant tactile exciter is determined by the above formula.

[0064] S2, Establish a theoretical model for precisely controlling the resonant frequency of the electromagnetic resonant tactile exciter:

[0065] Figure 4 A schematic diagram of the theoretical model for precisely controlling the resonant frequency of an electromagnetic resonant tactile exciter, wherein... Figure 4 (a) in the figure is a cross-sectional view of the model. Figure 4 (b) is the top view of the model; the resonant frequency of the electromagnetic resonant tactile exciter is mainly related to the magnet and the sector cantilever beam. A dynamic model of the magnet-sector cantilever beam system is established, where the mass of the magnet-sector cantilever beam dynamic system is equal to the mass of the magnet, expressed as: ,in ρ magnet The density of the magnet, Rmagnet Let be the radius of the magnet. H magnet The thickness is the magnet.

[0066] The resonant frequency of the electromagnetic resonant tactile exciter is shown in formula (2):

[0067] (2)

[0068] in, E PI Young's modulus of the material for the fan-shaped cantilever beam; H PI The thickness of the fan-shaped cantilever beam; θ The central angle of the fan-shaped cantilever beam; R magnet Let be the radius of the magnet; ρ magnet It is the density of the magnet; R inner The inner radius of the driving coil layer; For about θ The fitting expression, in this embodiment, is... ; For about θ The fitting expression, in this embodiment, is... ;

[0069] The E PI For material parameters (the system stiffness provided by the sector cantilever beam 6 depends on the material parameters), the R magnet , H PI , R inner , θ For geometric parameters. According to formula (2), by adjusting the geometric and material parameters in the theoretical model, the resonant frequency of the electromagnetic resonant tactile exciter can be precisely controlled, thereby maximizing the output electromagnetic force of the tactile exciter under the same power consumption. The theoretical calculation results for precisely controlling the resonant frequency of the electromagnetic resonant tactile exciter are as follows: Figure 5 As shown, where Figure 5 (a) provides the normalized frequency and dimensionless parameter. H PI / R inner ) 1.5 Linear relationship between them Figure 5 (b) provides the normalized frequency and dimensionless parameter. R magnet / R inner ) 1.5 Relationship curves Figure 5 (c) in the middle is to provide information about θ Fitting expression and .

[0070] The synergistic implementation of maximizing the normalized electromagnetic force of S1 and precisely tuning the resonant frequency of S2 enables the electromagnetic resonant tactile exciter to generate sufficiently significant tactile stimulation on the target contact object while maintaining low power consumption. Considering the high sensitivity of human skin to vibrations in the 100 Hz–300 Hz range (Meissner bodies and Pacini bodies have low activation thresholds and rapid adaptability), this method designs the resonant frequency within the 100–300 Hz range, thereby improving the system's energy efficiency while ensuring clear and perceptible tactile sensation.

[0071] Figure 6 The experimental measurement results of the frequency response characteristics of the electromagnetic resonant tactile exciter of the present invention are shown. As the driving current frequency gradually increases from a low frequency, the vibration displacement amplitude at the free end of the sector-shaped cantilever beam peaks at 200Hz. Near the 200Hz resonant frequency, the device can generate the maximum vibration amplitude; while away from resonance, the amplitude decreases rapidly. Specifically, under the same input power, the amplitude near the resonant frequency is significantly higher than the amplitude away from resonance, indicating that tuning to the resonant frequency of the electromagnetic resonant tactile exciter can greatly improve the output vibration effect without increasing power consumption.

[0072] Figure 7 The relationship between power consumption and vibration amplitude of the electromagnetic resonant tactile exciter of this invention is shown in the test at a resonant state (200Hz). The vibration displacement amplitude of the free end of the cantilever beam 1 was measured experimentally under different input power conditions. The results show that when the input power is 50mW, the electromagnetic resonant tactile exciter can achieve a peak-to-peak vibration displacement of 2.0mm; while when the input power is reduced to 0.01mW (i.e., on the order of 10µW), the device can still generate a vibration amplitude of 0.1mm. An amplitude of 0.1mm has reached the tactile threshold perceptible to the human hand, meaning that the electromagnetic resonant tactile exciter of this invention can provide perceptible vibration feedback to the user with power driven at the microwatt level. The above performance test data fully demonstrates the superiority of this invention in achieving efficient tactile output under low-power excitation. Compared with traditional electromagnetic resonant tactile exciters, the electromagnetic resonant tactile exciter of this invention can generate effective vibration feedback with lower energy consumption, exhibiting a significant energy efficiency advantage.

[0073] Applications of a low-power electromagnetic resonant haptic actuator, such as Figure 8 As shown, where, Figure 8 (a) is an exploded view of the soft, thin electronic skin. Figure 8 (b) is a schematic diagram of the geometric structure of the metal-flexible insulating film-metal composite layer. Figure 8 (c) is an exploded view of the electromagnetic resonant tactile exciter. Figure 8 (d) in the diagram is a functional schematic of the silicone elastic substrate; the low-power electromagnetic resonant tactile exciter is applied to an integrated soft, thin electronic skin.

[0074] The soft, thin electronic skin consists of an array of low-power electromagnetic resonant tactile exciters 1 arranged on a pre-perforated silicone elastic substrate 8. Adjacent low-power electromagnetic resonant tactile exciters 1 are connected by serpentine wires in a metal-flexible insulating film-metal composite layer 7. Specifically, a regular array of nine independent low-power electromagnetic resonant tactile exciters 1 in three rows and three columns (3×3) can conformally adhere to the natural curvature of the skin surface and provide tactile feedback in local areas. The arrays and units are interconnected with external circuits through serpentine connecting lines in the metal-flexible insulating film-metal composite layer 7. In this embodiment, the metal-flexible insulating film-metal composite layer 7 is a copper-polyimide-copper (Cu / PI / Cu) composite layer. The serpentine connecting lines have undergone geometric optimization based on quantitative rules, which significantly improves tensile performance and allows for adaptation to complex external large deformation conditions while ensuring circuit connectivity. The silicone elastic base of the electronic skin is approximately 0.12 mm thick, and its surface features a laser-precision-cut microporous array to enhance breathability while maintaining good fit and long-term wearing comfort. The silicone elastic base 8 employs a flexible silicone film structure.

[0075] This embodiment benefits from the high ductility of the silicone elastic substrate 8 and the serpentine interconnect structure. The proposed soft and thin electronic skin can operate stably under large deformation conditions, such as withstanding 60% uniaxial tension, bending with a bending radius of 12mm, or torsion of 90°, while maintaining the continuity of circuit connections and the stability of control signal transmission. In living joint areas such as the arm, elbow, and knee, the electronic skin can still stably maintain close conformal adhesion to the skin during the subject's natural movements, providing continuous and clear tactile feedback.

[0076] Figure 9 This paper presents the results of a frequency sweep experiment to evaluate the power consumption of tactile perception thresholds in different gender groups using the proposed exciter. Seven male and seven female subjects were recruited, and the electronic skin was worn on the pad of the right index finger. Alternating driving currents at different frequencies (100Hz, 150Hz, 200Hz, and 250Hz) were applied to the low-power electromagnetic resonant tactile exciter 1. The minimum driving power of the tactile stimulus perceived by each subject was recorded, and the average perception thresholds of different gender groups were compared and analyzed. The results show that female subjects generally exhibited lower perception thresholds across all frequency bands and were more sensitive to the vibrations generated by the device, verifying the reliable tactile feedback capability of the device at microwatt-level power consumption.

[0077] Figure 10 This study presents experimental results on the tactile perception threshold power consumption of subjects in different age groups at a frequency of 200 Hz using the proposed exciter. Subjects were grouped at 5-year intervals, and measurements and evaluations were conducted by progressively adjusting the alternating drive current. The results show that the average threshold power of the youth group was significantly lower than that of the middle-aged and elderly group. This conclusion validates that this device possesses good perceptibility across all population groups in the key physiological frequency band.

[0078] Based on the aforementioned soft and thin electronic skin, this invention has demonstrated haptic feedback in various application scenarios to highlight its advantages and effects in conformal skin adhesion and low power consumption. For example, Figure 11 The experimental results of installing the soft, thin electronic skin of the present invention on the back of a user's hand to display Braille characters are demonstrated. Figure 11 (a) shows the static pattern of the electromagnetic resonant tactile exciter used in the experiment displaying Braille characters. Figure 11 (b) reflects the experimental results of the actual pattern and the predicted pattern. In this embodiment, six low-power electromagnetic resonant tactile exciters 1 are arranged on a soft, thin electronic skin, corresponding to the arrangement of the Braille dot matrix. By driving different units to vibrate, tactile perception of corresponding Braille characters can be generated on the user's skin, successfully demonstrating the feasibility of an adhesive flexible Braille display. For example, Figure 12 Experimental results of the soft, thin electronic skin of the present invention for providing directional tactile feedback are shown, wherein, Figure 12 (a) provides a dynamic pattern for an electromagnetic resonant haptic exciter with directional haptic feedback. Figure 12 (b) provides the accuracy of directional guidance provided by the device in the hands, arms, chest, and back. In this embodiment, multiple low-power electromagnetic resonant tactile exciters 1 are distributed and attached to different parts of the human body (e.g., wrists, upper arms, etc.). By driving them in a specific sequence or combination to generate vibrations, directional guidance and other information can be transmitted to the user, realizing tactile navigation prompts in complex environments. These application examples show that the soft and thin electronic skin of the present invention has broad prospects in virtual reality immersive feedback, assisted sign language communication, wearable navigation, etc. It is particularly worth emphasizing that, due to the low power consumption and conformal skin adhesion of the system of the present invention, it can operate stably for a long time with almost no restriction on human activity, providing key support for the future development of wireless, lightweight, long-lasting, burden-free, and highly comfortable full-body wearable immersive tactile interaction systems.

[0079] The embodiments described above are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A low-power electromagnetic resonant tactile exciter, characterized in that, The low-power electromagnetic resonant tactile actuator (1) includes, from top to bottom, a thin film attachment layer (2), a magnet (3), a drive coil layer (4), and an anti-detachment bottom cover layer (5); specifically: The thin film attachment layer (2) is a sheet-like structure with a slit running through its center along the axial direction. The slit is not connected along the circumferential direction to form a fan-shaped cantilever beam (6). The thin film attachment layer (2) is divided into a free end and a fixed end by the slit. The free end and the fixed end are connected by the fan-shaped cantilever beam (6) and are an integrated structure. The fixed end is fixedly connected to the drive coil layer (4), and the free end is fixedly connected to the magnet (3). The driving coil layer (4) is an annular cylinder made of copper wire, which is placed around the magnet (3) and surrounds it. The inner cavity of the annular cylinder forms a space for the magnet to move. The magnet is located in the inner cavity of the annular cylinder, and the size of the inner cavity of the annular cylinder is larger than the size of the magnet (3). The anti-fall-off bottom cover layer (5) covers and fixes the bottom of the drive coil layer (4); The design method of the electromagnetic resonant tactile exciter Includes the following steps: S1. Establish a coil-magnet axisymmetric model to maximize the normalized electromagnetic force of the electromagnetic resonant tactile exciter and realize the low power consumption design of the electromagnetic resonant tactile exciter. The normalized electromagnetic force is calculated using formula (1): (1) In the formula, It is normalized electromagnetic force; F It is the electromagnetic force applied to the magnet generated by the driving coil layer; μ 0 is the permeability of free space; M It is the saturation magnetization of the magnet; P It is the power consumed by the electromagnetic resonant tactile exciter; ρ It is the resistivity of the wire wound into the drive coil; V magnet It is the volume of the magnet; f The resonant frequency of the electromagnetic resonant haptic exciter, relative to the height of the magnet. H magnet The radius of the magnet R magnet Height of the driving coil layer H coil Outer radius of the driving coil layer R outer Inner radius of the driving coil layer The distance between the geometric center of the magnet and the geometric center of the driving coil layer is z 0 related; The dimensionless design parameter combination that maximizes the normalized electromagnetic force of the electromagnetic resonant tactile exciter is determined by the above formula. S2, Establish a theoretical model for controlling the resonant frequency of the electromagnetic resonant tactile exciter: The mass of the magnet-sector cantilever beam dynamic system is equal to the mass of the magnet, expressed as: ,in ρ magnet The density of the magnet; R magnet Let be the radius of the magnet; H magnet The thickness of the magnet; The resonant frequency of the electromagnetic resonant tactile exciter is expressed as: (2) in, E PI Young's modulus of the material for the fan-shaped cantilever beam; H PI The thickness of the fan-shaped cantilever beam; θ The central angle of the fan-shaped cantilever beam; R magnet Let be the radius of the magnet; ρ magnet It is the density of the magnet; R inner The inner radius of the driving coil layer; For about θ The fitted expression; For about θ The fitted expression; Young's modulus E PI For material parameters, R magnet , H PI , R inner , θ The geometric parameters are: According to formula (2), the resonant frequency of the electromagnetic resonant tactile exciter is controlled by adjusting the material parameters and geometric parameters, thereby maximizing the electromagnetic force output of the electromagnetic resonant tactile exciter; Through the coordinated optimization design of S1 and S2, the electromagnetic resonant tactile exciter can generate sufficiently significant tactile excitation on the target contact object under low power consumption.

2. The low-power electromagnetic resonant tactile exciter according to claim 1, characterized in that, The driving coil layer (4) is arranged coaxially with the magnet (3).

3. The low-power electromagnetic resonant tactile exciter according to claim 1, characterized in that, The film attachment layer (2) is a flexible insulating film, and the materials include polyimide, polyethylene terephthalate, polymethyl methacrylate, and polypropylene; the anti-detachment bottom cover layer (5) is made of flexible insulating film material.

4. A low-power electromagnetic resonant tactile exciter according to claim 1, characterized in that, The magnet (3) is a permanent magnet with its central axis in the direction of magnetization. The central axis of the magnet is coaxial with the central axis of the driving coil layer (4). The driving coil layer (4) is supplied with alternating current to generate an alternating electromagnetic field, which drives the magnet (3) to vibrate back and forth under the action of electromagnetic force. The magnet (3) does not collide with the surrounding structure during the vibration process.

5. A low-power electromagnetic resonant tactile exciter according to claim 1, characterized in that, The inner arc surface of the fan-shaped cantilever beam (6) is connected to the free end, and the outer arc surface is connected to the fixed end. The left and right sides are straight segments, and the extension lines of the two straight segments form a central angle with the center of the thin film attachment layer (2). The central angle is used as an important structural design parameter to control the resonant frequency of the tactile exciter.

6. A wearable device, characterized in that, The low-power electromagnetic resonant tactile exciter described in any one of claims 1-5 is applied to an integrated soft and thin electronic skin. The soft and thin electronic skin consists of an array of several low-power electromagnetic resonant tactile exciters (1) arranged on a pre-perforated silicone elastic substrate (8). Adjacent low-power electromagnetic resonant tactile exciters (1) are connected by a serpentine connecting line of a metal-flexible insulating film-metal composite layer (7). In use, an alternating magnetic field is generated after an alternating current is passed through the driving coil layer (4), which drives the magnet (3) to reciprocate and transmit pressure and vibration signals to the target contact object (9). The wearable device is stretchable.

7. A wearable device according to claim 6, characterized in that, In the wearable device: The metal-flexible insulating film-metal composite layer (7) comprises an upper metal conductive layer, a flexible insulating film, and a lower metal conductive layer. It is integrally formed with the film attachment layer (2) by laser cutting process. The film attachment layer (2) is processed into a serpentine connecting line in the radial direction outward to achieve structural integration and is used to realize the circuit connection between tactile exciters. The serpentine connecting line has extensibility. The silicone elastic substrate (8) adopts a flexible silicone film structure, which provides mechanical support and fixation for the serpentine connecting line of the metal-flexible insulating film-metal composite layer (7) and the low-power electromagnetic resonance tactile exciter (1), while achieving smooth fit and conformal adhesion with the surface of the target contact object (9); the silicone elastic substrate (8) has several through-holes to keep the air flowing between the silicone elastic substrate (8) and the target contact object (9), reducing the stuffiness and dampness during long-term wear. At the same time, the silicone material itself has good softness and elasticity, which can avoid local pressure, thereby further improving the wearing comfort; The target contact object (9) is human skin or other objects that require tactile stimulation.

8. A wearable device according to claim 6, characterized in that, In the wearable device: the metal-flexible insulating film-metal composite layer (7) has metal conductive layers on both the upper and lower sides made of copper, gold, and silver; the flexible insulating film is made of polyimide, polyethylene terephthalate, polymethyl methacrylate, and polypropylene.

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