A faraday wave-imitated force sensing unit structure

Abstract

The application discloses a kind of force-sensitive unit structures of imitating faraday wave, including flexible substrate and the force-sensitive unit body of being arranged on flexible substrate, and the force surface of force-sensitive unit body is provided with imitating faraday wave ripple structure;The ripple structure has periodic or quasi-periodic surface relief characteristics, for guiding stress to spread to surrounding area along the surface and inside of the force-sensitive unit body under the action of load, to enhance the expansion effect of mechanical response signal in adjacent area.Compared with common surface relief structures such as planar, hemispherical, pyramidal and conical, the imitating faraday wave structure of the application can form a larger stress propagation area, thereby showing better mechanical response characteristics.

Description

Technical Field

[0001] This invention relates to the field of flexible sensing and intelligent sensing technology, and in particular to a force-sensitive unit structure that simulates Faraday waves to enhance physical crosstalk effects. Background Technology

[0002] With the development of embodied intelligence, precise robotic manipulation, and human-computer interaction technologies, the demand for large-area, high-resolution tactile sensor arrays in complex contact sensing, load localization, and load distribution recognition is constantly increasing. To achieve higher spatial resolution, tactile sensors typically employ an array structure composed of multiple force-sensitive units to enable precise perception of external contact events.

[0003] However, with the increase in sensing area and array density, the number of force-sensitive units increases significantly, posing considerable challenges to traditional array acquisition architectures in terms of wiring complexity, structural reliability, and system integration. For example, multi-channel independent acquisition methods lead to a rapid increase in the number of leads, while row-column multiplexing can reduce the number of leads, but it is still difficult to meet the high-precision recognition requirements for load position and load distribution in complex tactile scenarios due to limited array size, limited acquisition channels, and insufficient response characteristics of individual force-sensitive units.

[0004] Under conditions of a limited number of force-sensitive elements and a limited number of acquisition channels, the spatial information available for load location and distribution identification is relatively limited, relying solely on the local response of the loaded element itself. To improve tactile perception capabilities without significantly increasing the number of force-sensitive elements and leads, existing technologies have proposed methods for tactile information analysis utilizing physical crosstalk effects. These methods analyze the response characteristics of the loaded element and its multiple adjacent force-sensitive elements when a single point is subjected to load, thereby inverting the contact position, load magnitude, and load distribution.

[0005] Physical crosstalk essentially originates from the diffusion and propagation of stress in a flexible substrate, force-sensitive layer, or other sensing medium after an external load is applied. The area covered by stress propagation can be considered the physical receptive field of the force-sensitive unit. The larger the physical receptive field, the more adjacent force-sensitive units can be affected by a single load, and the richer the number of response channels and spatial distribution characteristics of the array output. By comparing the response intensity, response gradient, and response combination relationship of different adjacent force-sensitive units, more complete load spatial information can be obtained, thereby improving the accuracy and stability of load location, load distribution recognition, and tactile information reconstruction under the conditions of limited array size and limited acquisition channels. Therefore, expanding the physical receptive field is not simply to increase the response range, but to enable more force-sensitive units to participate in the coordinated response of the same load event, forming redundant and differentiated response characteristics that can be used for spatial location and distribution analysis.

[0006] An existing high-performance flexible piezoresistive pressure sensor and its fabrication method (CN202610985760.5) utilizes a micropyramid structure fabricated on the surface of a PDMS / multi-walled carbon nanotube piezoresistive composite film. This micropyramid deforms under pressure, increasing the contact area and altering the internal conductive pathways to improve the sensor's sensitivity and detection range. However, this technology primarily utilizes local microstructure deformation to improve the electrical response of the stressed region, without addressing structural design considerations for expanding the stress propagation range to adjacent areas or increasing the number of force-sensitive units participating in the coordinated response.

[0007] An existing flexible piezoresistive pressure sensor based on a double-layer corrugated structure (Linear Range Enhancement in Flexible Piezoresistive Sensors Enabled by Double-Layer Corrugated Structure. Doi: https: / / doi.org / 10.1002 / adfm.202513480DigitalObjectIdentifier (DOI)) improves pressure distribution, load transfer, and stress dispersion through a double-layer corrugated structure with different heights, thereby expanding the sensor's linear response range. This technology demonstrates that the corrugated structure can regulate the force deformation and stress distribution in the flexible sensor. However, it primarily focuses on pressure detection range and response linearity, without disclosing the construction of periodic or quasi-periodic corrugated undulation structures based on Faraday wave morphology, nor does it utilize the corrugated structure to expand the physical sensing field of the array force-sensitive cells or enhance the physical crosstalk response between adjacent force-sensitive cells.

[0008] However, in practical applications, due to limitations in the thickness of the force-sensitive unit, the mechanical properties of the material, and the structural morphology of the stressed surface, the propagation distance of stress in the sensing medium is usually short, resulting in a narrow physical sensing field. In this case, the number of adjacent force-sensitive units that can participate in the response under a single load is limited, and the differences in response intensity and spatial overlap between different units are insufficient. This makes it difficult to provide sufficient spatial information for identifying the load location and load distribution, thus affecting the accuracy, stability, and super-resolution capability of subsequent tactile information analysis.

[0009] Therefore, it is necessary to propose a force-sensitive unit structure that can enhance the stress propagation range and expand the physical sensing field, so that a single load can generate a detectable response with spatial differences in more adjacent force-sensitive units. Without significantly increasing the number of array units, the number of acquisition channels and the wiring complexity, the collaborative response characteristics of the array output are enriched, and the sensor array's ability to recognize load position, load distribution and complex tactile information is improved. Summary of the Invention

[0010] The purpose of this invention is to provide a force-sensitive unit structure that mimics Faraday waves, in order to solve the problems of insufficient control over stress propagation range, limited response extension capability, and weak physical crosstalk effect in existing force-sensitive structures.

[0011] The present invention is achieved by at least one of the following technical solutions.

[0012] A Faraday wave-inspired force-sensitive unit structure includes a flexible substrate and a force-sensitive unit body disposed on the flexible substrate. The force-bearing surface of the force-sensitive unit body is provided with a Faraday wave-inspired corrugated undulation structure. The corrugated undulation structure has periodic or quasi-periodic surface undulation characteristics, which are used to guide stress to propagate along the surface and interior of the force-sensitive unit body to the surrounding area under load, so as to enhance the expansion effect of the mechanical response signal in the adjacent area.

[0013] Furthermore, the undulating structure is a structure constructed based on the morphological characteristics of Faraday waves.

[0014] Furthermore, the Faraday wave morphological characteristics include at least one of periodic or quasi-periodic standing wave patterns having a defined wavelength, amplitude, and symmetry.

[0015] Furthermore, the undulating structure corresponds to the wavy pattern morphology formed by the combined action of gravity and surface tension under vibration excitation conditions.

[0016] Furthermore, the flexible substrate and / or the force-sensitive unit body are made of flexible elastic materials, flexible polymer materials, flexible composite materials, or conductive elastic materials.

[0017] Furthermore, the material of the force-sensitive unit body includes silicone, conductive silicone, polydimethylsiloxane, polyurethane, thermoplastic elastomer, rubber-based composite material, or a combination thereof.

[0018] Furthermore, the corrugated undulation structure is disposed on the force transmission structure of the force-sensitive unit body to extend the stress propagation under load.

[0019] A sensor comprising the aforementioned force-sensitive unit structure mimicking a Faraday wave.

[0020] A mechanical sensing system includes the aforementioned sensor and a signal processing unit; the signal processing unit is used to receive and process the response signal generated by the sensor under stress, and to identify load location and / or load distribution information based on the response signal.

[0021] An electronic device comprising the aforementioned mechanical sensing system.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects: 1. By setting a Faraday wave-like undulating structure on the stress-bearing surface of the force-sensitive unit, stress can be guided to propagate along the surface and interior to the surrounding area under load, thereby expanding the stress influence range.

[0023] 2. By constructing a periodic or quasi-periodic surface undulation structure with a preset wavelength and amplitude, this invention is beneficial to enhancing the expansion effect of the mechanical response signal in adjacent regions and improving the physical crosstalk response intensity.

[0024] 3. Compared with common surface undulation structures such as planar, hemispherical, pyramidal and conical shapes, the Faraday wave-like structure described in this invention can form a larger stress propagation area, thereby exhibiting superior mechanical response characteristics.

[0025] 4. This invention has strong adaptability to material systems and is not limited to a single material type, making it easy to adjust according to different application scenarios.

[0026] 5. This invention can be applied to tactile sensing, load positioning, contact distribution recognition and related intelligent sensing fields. Attached Figure Description

[0027] Figure 1 This is a reference schematic diagram of a common Faraday wave morphology in an embodiment of the present invention; Figure 2 This is a schematic diagram of a two-dimensional interface and a three-dimensional curved surface of a simulated Faraday wave undulation structure for an embodiment. Figure 3 This is a schematic diagram of the surface forming process of the simulated Faraday wave undulation structure in an embodiment. Figure 4 This is a schematic diagram of the load on the center of the simulated Faraday wave structure in an embodiment of the present invention, and a schematic diagram of the stress distribution at different horizontal heights. Figure 5 This is a cloud map of the stress distribution on the bottom surface of the simulated Faraday wave structure in an embodiment of the present invention, and a schematic diagram of the effective coverage area obtained by screening based on a 10% peak stress threshold. Figure 6 This is a comparison diagram of the stress distribution in the region where the simulated Faraday wave ripple structure and other common force-sensitive structures are greater than 10% in finite element simulation. Specific implementation methods The present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Without departing from the concept of the present invention, those skilled in the art can make various modifications or substitutions to the structural form, material types, surface morphology parameters, and application methods of the present invention, all of which should fall within the scope of protection of the present invention.

[0028] This embodiment provides a Faraday wave-inspired force-sensitive unit structure, including a flexible substrate and a force-sensitive unit body disposed on the flexible substrate. The force-sensitive unit body has a Faraday wave-inspired undulating structure on its stress-bearing surface, meaning the undulating structure is constructed based on the morphological characteristics of a Faraday wave. This undulating structure, disposed on the stress-bearing surface of the force-sensitive unit body, expands the stress propagation range under load and enhances the physical crosstalk response of the force-sensitive unit under stress. The undulating structure corresponds to the wave pattern morphology formed by the combined action of gravity and surface tension under vibration excitation conditions.

[0029] like Figure 1 As shown, Faraday waves can form various common morphologies under different excitation conditions, including striped, square, hexagonal, eight-fold, ten-fold, and twelve-fold patterns. It should be noted that the simulated Faraday wave undulation structure of this invention is not limited to a single pattern, but rather refers to surface undulation structures constructed based on Faraday wave morphological characteristics, specifically various periodic or quasi-periodic surface undulation structures. The Faraday wave morphological characteristics can be striped, square, hexagonal, eight-fold, ten-fold, twelve-fold, or other periodic or quasi-periodic patterns formed by the standing wave behavior of a liquid surface under vibration excitation conditions.

[0030] In some implementations, to describe the different types of pseudo-Faraday wave morphologies described above, the ripple structure can be approximated using a function obtained by superimposing multiple cosine waves with different propagation directions. Here, the ripple structure is assumed to be located at a plane coordinate position... The height at is , For wave number, and , If the characteristic wavelength of the ripple structure is given, then different typical Faraday wave morphologies can be represented as follows.

[0031] The striped Faraday wave structure can be represented as:

[0032] The lattice-type Faraday wave structure can be represented as:

[0033] The hexagonal Faraday wave structure can be represented as:

[0034] The octave-type Faraday wave structure can be represented as:

[0035] The ten-fold Faraday wave structure can be represented as:

[0036] The twelve-fold Faraday wave structure can be represented as:

[0037] in is the number for the direction of cosine wave propagation, and is a non-negative integer index used to identify the cosine wave components corresponding to different propagation directions.

[0038] like Figure 2 As shown, in this embodiment, a grid-shaped Faraday wave pattern is preferably selected as a reference object for the corrugated undulation structure of the force-sensitive unit to illustrate the configuration and mechanical response characteristics of the corrugated undulation structure of the present invention. However, the scope of protection of the present invention is not limited to this specific drawing. Figure 2 (a) and (b) illustrate the two-dimensional interface and three-dimensional surface reference morphology of the corrugated structure under the preferred embodiment. The corrugated structure references the typical standing wave texture formed by Faraday waves on a liquid surface, and through structural design, it is transformed into periodic or quasi-periodic undulation features suitable for solid force-sensitive structural surfaces.

[0039] It should be noted that the Faraday wave-like undulating structure described in this invention may approximate a sine curve in its local cross-sectional morphology, but it is not equivalent to an ideal sine curve. A sine curve is a regular periodic curve described by a single mathematical function, and its waveform, period, and amplitude typically change according to a fixed functional relationship. In contrast, Faraday waves originate from the standing wave behavior of a liquid surface under vibrational excitation conditions, and are influenced by factors such as gravity, surface tension, excitation parameters, and boundary conditions. Therefore, although its surface morphology may locally exhibit continuous undulating characteristics similar to a sine curve, it possesses stronger physical origin characteristics and morphological extensibility overall. The Faraday wave-like structure described in this invention is not limited to a standard sine curve, but refers to a periodic or quasi-periodic surface structure capable of characterizing the morphological characteristics of Faraday waves and used to guide stress propagation.

[0040] In this invention, the corrugated structure has a preset wavelength and a preset amplitude, used to guide stress to propagate along the surface and interior of the force-sensitive unit body to the surrounding area under external load. Compared with planar or locally protruding surface morphologies, this type of corrugated structure is beneficial for changing the stress diffusion path after being subjected to force, thereby enhancing the expansion effect of the mechanical response signal in adjacent areas and improving the physical crosstalk response of the force-sensitive unit under stress. In a preferred embodiment, the planar dimensions of the force-sensitive unit body are... The corrugated structure forms 11 cycles on the surface of the force-sensitive unit body, with a cycle length of [wavelength missing], i.e., wavelength [wavelength missing]. The height of the wave crest relative to the reference surface is The aforementioned wavelength and peak height are preferred structural parameters used in mechanical simulation and sensing field range verification to form a stable and continuous stress diffusion path within a force-sensitive unit of finite size. It should be noted that the wavelength, peak height, number of periods, and size of the force-sensitive unit can be adjusted according to material properties, device size, and target sensing field range, and do not constitute a limitation on the scope of protection of this invention.

[0041] In some embodiments, the flexible substrate and / or the force-sensitive unit body are made of flexible elastic materials, flexible polymer materials, flexible composite materials, conductive elastic materials, or combinations thereof. Preferably, the materials include silicone, conductive silicone, polydimethylsiloxane, polyurethane, thermoplastic elastomers, rubber-based composite materials, or combinations thereof. It should be noted that the key to this invention lies in the mechanical response advantages brought about by the Faraday wave-like undulating structure, rather than in limiting the use of a specific material. Therefore, the material system can be selected according to actual application requirements.

[0042] The Faraday wave-like undulating structure of this embodiment can be prepared by mold imprinting, micro-nano imprinting, casting replication, surface forming, laser processing, or other processing techniques that can form a undulating structure with a preset wavelength and preset amplitude on the stress-bearing surface of the force-sensitive unit body. It should be noted that this invention does not rely on any specific processing technique as its core protection; as long as the Faraday wave-like undulating structure can be formed on the stress-bearing surface of the force-sensitive unit body, and the corresponding stress diffusion and physical crosstalk enhancement effects are achieved, it falls within the protection scope of this invention. Figure 3 As shown, in a preferred embodiment, the simulated Faraday wave undulation structure is fabricated on the force-sensitive unit body formed of conductive silicone using a laser scanning processing method. The laser processing system includes a fiber laser source, a beam expander, a galvanometer scanning assembly, and... Lens and laser control module. The fiber laser source outputs the processing laser beam; the beam expander adjusts the laser beam's spot size and divergence angle; the galvanometer scanning assembly changes the laser beam's scanning position on the conductive silicone surface according to a preset scanning path; the... The lens is used to focus the laser beam deflected by the galvanometer onto the force-bearing surface of the conductive silicone to achieve two-dimensional scanning processing within a preset area.

[0043] Specifically, firstly, based on the preset wavelength, peak height, and pattern morphology of the target Faraday wave-like undulation structure, a corresponding scanning path or height field processing pattern is constructed, and the processing pattern is input into the laser control module. Then, the laser beam is controlled to perform a linear scan along a first direction, forming a one-dimensional cosine profile with a preset period and depth on the stressed surface of the conductive silicone. Afterward, the laser beam is controlled to perform a second linear scan along a second direction intersecting the first direction, causing the cosine profiles in the two directions to superimpose, thereby forming a Faraday wave-like undulation structure with two-dimensional periodic or quasi-periodic undulation characteristics on the conductive silicone surface.

[0044] During the processing, the processing depth, ripple period, peak height and surface morphology of the conductive silicone surface can be controlled by adjusting parameters such as laser power, scanning speed, scanning spacing, number of scans, scanning direction and focusing position, so as to obtain the target Faraday wave ripple structure.

[0045] like Figure 4 As shown, to further illustrate the stress transfer behavior of the simulated Faraday wave structure described in this invention under load, the stress distribution at different heights of the horizontal plane under load at its center was analyzed. Figure 4 (a) shows a schematic diagram of the load at the center of the structure and the overall stress response. Figure 4 (b) shows the stress distribution at different height sections. It can be seen that under load, the stress is not limited to the vicinity of the loading point, but gradually diffuses towards the surrounding area along the structural height, exhibiting different spatial distribution characteristics at different horizontal planes. This result indicates that the simulated Faraday wave structure can guide local loads to the interior and surrounding areas of the structure through its periodic undulating surface, thus forming a significant stress propagation effect.

[0046] Furthermore, as the observation section moves from the top to the bottom, the stress distribution range gradually expands, indicating that the simulated Faraday wave structure is conducive to transforming local stress into continuous stress transmission over a larger range, providing a basis for forming a large effective stress coverage area on the bottom surface.

[0047] To quantitatively characterize the stress propagation capability of different force-sensitive structures under load, this embodiment uses the stress distribution cloud map of the bearing bottom surface as the evaluation basis for the mechanical sensing field range. Specifically, within the effective evaluation area... Internally, extract the peak stress of the bottom surface stress field. and will As a stress excitation threshold; stress greater than The region is defined as the effective mechanical sensing region of the structure under the stated load conditions. The area of ​​the effective mechanical sensing region is statistically analyzed to obtain the effective coverage area. and based on area percentage As a quantitative characterization index of the mechanical sensing field, the physical significance of the above evaluation method lies in the fact that, after excluding lower-level background stress, only the stress region that still makes a significant contribution to load transfer is retained, thus more objectively reflecting the actual impact of the structure on its stress diffusion capability.

[0048] like Figure 5 As shown, the stress distribution on the bottom surface of the simulated Faraday wave structure described in this invention was analyzed under uniform load conditions. The results show that the stress distribution on the bottom surface exhibits high spatial consistency with the trough positions of the surface waveform. The stress peaks are continuously distributed along the trough projection area, and significant stress extension is formed in both the transverse and longitudinal trough regions. This result further illustrates that the simulated Faraday wave undulating structure can guide the load to diffuse to the surrounding area through alternating undulations and continuous curvature, thereby promoting the redistribution and propagation of stress between adjacent areas.

[0049] In this embodiment, the total area of ​​the evaluation region It is 23.04mm. 2 After screening using 10% of the peak stress as the stress excitation threshold, the effective coverage area of ​​the Faraday wave-like structure was determined. It is 19.09mm. 2 corresponding area percentage The result is 82.51%. This result indicates that, under the structural dimensions and load conditions corresponding to this embodiment, the Faraday wave-like structure can form a large and continuous stress diffusion region on the bottom surface, thus exhibiting superior mechanical sensing field characteristics.

[0050] like Figure 6 As shown in Table 1, in order to compare the mechanical sensing field sizes of different force-sensitive structures under uniform scale and load conditions, this embodiment selects four representative common structures in flexible pressure sensors as a control group. Figure 6 (a), (b), (c), and (d) represent planar, hemispherical, pyramidal, and conical structures, respectively. Each control structure maintains the same geometric scale as the simulated Faraday wave structure described in this invention, with consistent settings for key parameters such as overall effective size, structural height, period size, and peak height. This minimizes the impact of size differences on the simulation results, allowing the comparison results to more realistically reflect the influence of different surface morphologies on stress diffusion capabilities.

[0051] Table 1. Comparison of quantitative mechanical sensing fields between the Faraday wave-like undulating structure and other common force-sensitive structures.

[0052] Under the same load and boundary conditions, the effective coverage area of ​​planar structures, hemispherical structures, pyramidal structures, and conical structures... They are 9.66mm respectively 2 11.57 mm 2 11.55 mm 2 and 12.92mm 2 The corresponding area percentage The percentages are 41.92%, 50.21%, 50.15%, and 56.06%, respectively; while the effective coverage area of ​​the Faraday wave-like structure described in this invention is... It is 19.09 mm. 2 Area percentage It is 82.51%.

[0053] Furthermore, using common force-sensitive structures as a reference, the effective mechanical sensing field area of ​​the Faraday wave-like structure described in this invention is increased by 96.84%, 64.33%, 64.53%, and 47.17%, respectively. These results indicate that, while maintaining consistent geometric dimensions and load conditions, traditional structures can form stress concentrations in local areas, but their stress diffusion is more easily limited by local protruding geometry and transition regions, resulting in a relatively small effective coverage area on the bottom surface. In contrast, the Faraday wave-like structure described in this invention, with its alternating undulations and continuous curvature constructing a cross-period stress transfer path, can more fully transform local loads into a larger-scale continuously diffused stress field, thereby significantly expanding the effective mechanical sensing field.

[0054] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A force-sensitive unit structure mimicking Faraday waves, characterized in that, The device includes a flexible substrate and a force-sensitive unit body disposed on the flexible substrate. The force-sensitive unit body has a Faraday wave-like undulating structure on its stress-bearing surface. The undulating structure has periodic or quasi-periodic surface undulation characteristics, which are used to guide stress to propagate along the surface and interior of the force-sensitive unit body to the surrounding area under load, so as to enhance the expansion effect of the mechanical response signal in the adjacent area.

2. The force-sensitive unit structure mimicking a Faraday wave as described in claim 1, characterized in that, The undulating structure is a structure constructed based on the morphological characteristics of Faraday waves.

3. The force-sensitive unit structure mimicking a Faraday wave as described in claim 2, characterized in that, The Faraday wave morphological characteristics include at least one of periodic or quasi-periodic standing wave patterns with defined wavelength, amplitude, and symmetry.

4. The force-sensitive unit structure mimicking a Faraday wave as described in claim 1, characterized in that, The undulating structure corresponds to the wavy pattern formed by the combined action of gravity and surface tension under vibration excitation conditions.

5. The force-sensitive unit structure mimicking a Faraday wave according to claim 1, characterized in that, The flexible substrate and / or force-sensitive unit body are made of flexible elastic materials, flexible polymer materials, flexible composite materials, or conductive elastic materials.

6. The force-sensitive unit structure of the simulated Faraday wave according to claim 5, characterized in that, The material of the force-sensitive unit body includes silicone, conductive silicone, polydimethylsiloxane, polyurethane, thermoplastic elastomer, rubber-based composite material, or a combination thereof.

7. The force-sensitive unit structure mimicking a Faraday wave according to claim 1, characterized in that, The corrugated structure is set in the force transmission structure of the force-sensitive unit body to extend the stress propagation under load.

8. A sensor, characterized in that, Including the force-sensitive unit structure of the simulated Faraday wave as described in any one of claims 1 to 10.

9. A mechanical sensing system, characterized in that, It includes the sensor as described in claim 11, and a signal processing unit; the signal processing unit is used to receive and process the response signal generated by the sensor under stress, and to identify the load location and / or load distribution information based on the response signal.

10. An electronic device, characterized in that, Including the mechanical sensing system as described in claim 9.

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