A composite tactile sensor integrating interlocking structures and array electrodes

Abstract

This invention discloses a composite tactile sensor integrating an interlocking structure and an array of electrodes, belonging to the field of sensor technology. It includes, from top to bottom, a biomimetic fingerprint layer, an interlocking piezoelectric module, an insulating layer, and an array of capacitor modules. The biomimetic fingerprint layer has a surface with concave and convex microstructures; the interlocking piezoelectric module includes an interlocking upper piezoelectric component and a lower piezoelectric component; the insulating layer is a rectangular plate structure; the array of capacitor modules is an array-type capacitance detection structure, including an upper array electrode, a dielectric layer, and a lower array electrode. When an external force is continuously applied to the sensor, the interlocking piezoelectric module outputs a pre-triggered signal, and the array of capacitor modules is energized to detect the capacitance change of each array of capacitor units to characterize the magnitude of the continuous force, and determines the location of the force application based on the relative changes in the capacitance units. This invention achieves complementary acquisition of dynamic and static force information, significantly reducing system power consumption and improving energy utilization.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a composite tactile sensor that integrates an interlocking structure and an array of electrodes. Background Technology

[0002] With the development of robotic electronic skin, intelligent prosthetics, wearable devices, and dexterous grasping systems, multi-information tactile sensors capable of simultaneously sensing transient contact, continuous pressure, and position of action have attracted widespread attention. Existing tactile sensing technologies mainly include piezoresistive, capacitive, and piezoelectric sensors. Among them, piezoelectric sensors have fast response speeds, high sensitivity, and can generate their own power, making them suitable for detecting dynamic force signals such as impacts and vibrations. However, their output depends on the change in force and they have weak sensing capabilities for continuous static pressure, often making it difficult to accurately characterize the magnitude and position of pressure during stable contact. While capacitive sensors can achieve better static pressure detection and obtain information such as pressure distribution and contact position through array design, they typically require continuous power supply and periodic scanning, resulting in high power consumption and limitations in low-power, long-duration operating scenarios. Furthermore, their response capability to rapid transient forces is relatively insufficient.

[0003] Single-mechanism tactile sensors generally face the dilemma of "not being able to achieve both dynamic and static effects"—piezoelectric sensors are "fast but not stable," while capacitive sensors are "stable but have insufficient dynamic response and high power consumption." Although existing composite sensors simply "piece together" the two types of sensing elements in terms of function, due to the lack of targeted microstructure design, they still expose a series of insurmountable problems in practical applications.

[0004] Firstly, regarding the contact interface and slip control, existing composite sensors mostly use traditional planar configurations for their surface or intermediate structures, lacking biomimetic textures (such as fingerprint ridges, papillae, and other microstructures). This makes it impossible for the sensor to effectively control the friction and stress distribution at the contact interface during grasping or dynamic contact, making it prone to micro-slippage or macro-slippage. Micro-slippage causes severe fluctuations and non-repeatable noise in capacitance and piezoelectric signals, making it difficult for the sensor to stably acquire pressure, texture, and contact state information, severely reducing the reliability of grasping control.

[0005] Secondly, regarding mechanical transmission and sensitivity, traditional planar piezoelectric units typically employ thin-film or bulk structures. Under stress, the deformation of the piezoelectric material is relatively limited, and the stress transmission efficiency from the encapsulation layer to the piezoelectric layer is low. This results in the piezoelectric material's electromechanical conversion potential not being fully realized, hindering the improvement of sensor sensitivity. Simultaneously, signal coupling exists between the normal and tangential responses of the capacitive unit, lacking effective decoupling methods.

[0006] Furthermore, regarding interface and energy efficiency, while ordinary capacitor arrays can acquire spatial distribution information, their operating mode is often a continuous full-matrix scan, lacking an event-driven triggering mechanism. For the vast majority of the time, the sensor contact area or pressure remains unchanged, resulting in significant wasted power consumption from continuous scanning. Simultaneously, the transient signals generated by the piezoelectric units are typically not used for active wake-up or gated capacitor arrays. The lack of deep integration in collaborative triggering and energy management between the two sensing units leads to low overall energy efficiency.

[0007] Finally, regarding structural collaboration and information fusion, existing composite sensors are mostly simple physical superpositions of piezoelectric and capacitive layers. The mechanical and electrical connections between functional layers are not tight enough, and there is a lack of structural collaboration in the integrated design of the entire path from force to deformation to signal conversion. This results in significant deficiencies in dynamic-static multi-mode switching, normal-tangential multi-dimensional force decoupling, and time synchronization and weighted fusion of dynamic and static signals. Ultimately, this leads to unsatisfactory overall sensor performance—including static and dynamic detection range, sensitivity, multi-dimensional force detection accuracy, and energy utilization—making it difficult to meet the stringent requirements of high-end application scenarios such as dexterous grasping in endoscopic robots, precise manipulation in intelligent prosthetics, and accurate perception in wearable devices. Summary of the Invention

[0008] To address the problems of existing single piezoelectric tactile sensors being unable to accurately characterize continuous force and application location, single capacitive tactile sensors requiring continuous power for scanning and having high power consumption, and insufficient response to dynamic instantaneous force, this invention proposes a composite tactile sensor integrating an interlocking structure and an array of electrodes to achieve coordinated perception of instantaneous dynamic force and continuous static force, while also considering application location identification, force distribution analysis, and energy consumption reduction.

[0009] The technical solution adopted by this invention to solve its technical problem is: a composite tactile sensor integrating an interlocking structure and an array electrode, comprising, from top to bottom, a biomimetic fingerprint layer, an interlocking piezoelectric module, an insulating layer, and an array capacitor module. The surface of the biomimetic fingerprint layer is provided with concave-convex microstructures to increase the surface friction between the sensor and the object being measured and to enhance the deformation response of the internal piezoelectric material and capacitor plates. The interlocking piezoelectric module includes an interlocking upper piezoelectric component and a lower piezoelectric component. The insulating layer is a rectangular plate structure used to achieve electrical isolation between the interlocking piezoelectric module and the array capacitor module. The array capacitor module is an array-type capacitance detection structure, including an upper array electrode, a lower array electrode, and a dielectric layer disposed between the two. When an external force is continuously applied to the sensor, the interlocked piezoelectric module outputs a pre-triggered signal, and the array capacitor module is energized to detect the capacitance change of each array capacitor unit to characterize the magnitude of the continuous force, and to determine the position of the force based on the relative change relationship of each capacitor unit.

[0010] The aforementioned composite tactile sensor integrating an interlocking structure and an array of electrodes has a concentric ring-shaped, arc-shaped, or fingerprint-like microstructure, with a protrusion height of 5μm-500μm, a spacing of 20μm-1000μm between adjacent protrusions, and a single ridge width of 20μm-800μm.

[0011] The aforementioned composite tactile sensor integrating an interlocking structure and an array of electrodes has an arched interlocking structure between the upper and lower piezoelectric components. The bottom of the upper piezoelectric component forms a set of spaced-apart protrusions, and the top of the lower piezoelectric component has another set of protrusions that match the protrusions. The two sets of protrusions are staggered to form an interlocking contact interface.

[0012] The aforementioned composite tactile sensor integrating an interlocking structure and an array of electrodes has a trapezoidal interlocking structure between the upper and lower piezoelectric components. The bottom of the upper piezoelectric component forms a set of spaced protrusions, and the top of the lower piezoelectric component has another set of protrusions that match the protrusions. The two sets of protrusions are staggered to form an interlocking contact interface.

[0013] The aforementioned composite tactile sensor integrating an interlocking structure and an array of electrodes includes an upper piezoelectric component comprising an upper electrode layer and an upper piezoelectric sheet connected in sequence, and a lower piezoelectric component comprising a lower electrode layer and a lower piezoelectric sheet connected in sequence. The thickness of the upper and lower piezoelectric sheets is 20μm-500μm, and the thickness of the upper and lower electrode layers is 100nm-50μm.

[0014] The aforementioned composite tactile sensor integrating an interlocking structure and an array of electrodes has an insulating layer made of a flexible and insulating polymer thin-film material with a thickness of 10μm-1mm.

[0015] The aforementioned composite tactile sensor integrates an interlocking structure and an array of electrodes. The upper and lower array electrodes constitute multiple capacitor units, and the capacitance change value of each capacitor unit is used to characterize tactile information. By measuring the capacitance change value and its spatial distribution, information such as the position of the point of application, the magnitude of the pressure, the pressure distribution, and the direction of the force are obtained. The magnitude of the normal pressure is determined by the deformation caused by the force and the change in the distance between the electrodes. The position of the point of application of the force is determined by the area where the unit with the largest capacitance change is located. The magnitude and direction of the tangential force are characterized by the change in the area of ​​the electrodes facing each other.

[0016] The aforementioned composite tactile sensor integrating an interlocking structure and an array electrode includes an upper array electrode and a lower array electrode, each comprising a flexible substrate and an array of capacitive plates disposed on the flexible substrate, wherein the flexible substrate is made of PI material.

[0017] The aforementioned composite tactile sensor integrating an interlocking structure and an array electrode has an upper array electrode and a lower array electrode with plate shapes including rectangular, comb-shaped, fan-shaped, arc-shaped, cross-shaped, asymmetrical polygonal or a combination thereof. The maximum external length of the upper array electrode and the lower array electrode is 100μm to 10mm, and the maximum external width is 100μm to 10mm.

[0018] The beneficial effects of the present invention are: (1) The present invention sets a biomimetic fingerprint layer on the sensor surface, which on the one hand increases the contact friction and improves the contact stability; on the other hand, the fingerprint-like concave and convex microstructure enhances the force concentration and structural deformation, further improving the overall detection accuracy and reliability. By setting an arched interlocking structure, the upper and lower piezoelectric sheets form a directional meshing and mechanical amplification effect when subjected to force, which strengthens the d31 transverse strain mode of the piezoelectric film and improves the piezoelectric output amplitude and response sensitivity.

[0019] (2) The present invention forms multiple sets of capacitor units by means of upper array electrodes, lower array electrodes and flexible dielectric layer. It can not only detect the magnitude of continuous force, but also identify the force position, pressure distribution and force direction according to the relative change relationship of each capacitor unit, and obtain richer tactile information than a single piezoelectric or single-point capacitor structure.

[0020] (3) By combining the interlocked piezoelectric module and the array capacitor module, the piezoelectric part is responsible for instantaneous impact, dynamic force and rapid response detection, while the capacitor part is responsible for continuous force, static pressure and spatial distribution detection. This overcomes the limitations of a single sensing mechanism in dynamic response or static maintenance, and achieves complementary acquisition of dynamic and static force information.

[0021] (4) The present invention adopts a piezoelectric pre-triggered and capacitor on-demand start working mode. It uses the pre-triggered signal output by the interlocked piezoelectric module at the moment of contact to trigger the capacitor array detection, avoiding the long-term continuous power supply scanning of the array capacitor module, significantly reducing system power consumption and improving energy utilization. It is especially suitable for battery-powered scenarios such as wearable devices and robot electronic skin. Attached Figure Description

[0022] Figure 1 Front view of a dexterous hand with a composite tactile sensor installed; Figure 2 This is an exploded view of the tactile sensor of the present invention; Figure 3 Axonometric view of a biomimetic fingerprint layer; Figure 4Exploded view of the interlocked piezoelectric module; Figure 5 Axonometric drawing of the lower piezoelectric sheet; Figure 6 This is an assembly diagram of the upper and lower piezoelectric sheets; Figure 7 This is an exploded view of the array capacitor module; Figure 8 This is a cross-sectional view of the array capacitor module; Figure 9 Axonometric view of the lower array electrodes; Figure 10 Top view of the lower array electrodes; Figure 11 Flowchart for fabricating a composite tactile sensor; Figure 12 This is an assembly diagram of the upper and lower piezoelectric sheets in Example 2; Figure 13 This is an isometric view of the lower piezoelectric sheet in Example 2; Figure 14 This is a top view of the lower piezoelectric sheet in Example 2; Figure 15 This is an isometric view of the lower array electrodes in Example 3; Figure 16 This is a top view of the lower array electrodes in Example 3; Among them, 1. Dexterous hand; 2. Composite tactile sensor integrating interlocking structure and array electrodes; 2-1. Bionic fingerprint layer; 2-2. Interlocking piezoelectric module; 2-2-1. Upper electrode layer; 2-2-2. Upper piezoelectric sheet; 2-2-3. Lower piezoelectric sheet; 2-2-4. Lower electrode layer; 2-3. Insulating layer; 2-4. Array capacitor module; 2-4-1. Upper array electrode; 2-4-2. Dielectric layer; 2-4-3. Lower array electrode. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1: like Figures 1 to 11As shown, this embodiment provides a composite tactile sensor 2 integrating an interlocking structure and an array of electrodes. This composite tactile sensor 2 can be installed on the fingertips, fingertips, or other locations requiring contact sensing in a dexterous hand 1, enabling comprehensive detection of transient dynamic forces, continuous static forces, and the location of application, pressure distribution, and tangential force state during contact. The composite tactile sensor can be a single tactile sensing unit or an array of multiple tactile sensing units arranged in an array. The planar dimensions of a single tactile sensing unit can range from 1mm×1mm to 20mm×20mm, preferably from 3mm×3mm to 10mm×10mm; when multiple tactile sensing units are arranged in an array, the overall sensing area size can be expanded according to the installation location and detection requirements, for example, from 10mm×10mm to 100mm×100mm.

[0025] like Figure 2 As shown, the composite tactile sensor 2 integrating an interlocking structure and an array of electrodes comprises, from top to bottom, a biomimetic fingerprint layer 2-1, an interlocking piezoelectric module 2-2, an insulating layer 2-3, and an array capacitor module 2-4. The layers are connected via silicon-based elastic materials, flexible adhesive layers, or other methods suitable for flexible device packaging, forming a multi-layer composite sensing structure with certain flexibility, bendability, and stable mechanical coupling capabilities.

[0026] Among them, such as Figure 3 As shown, the biomimetic fingerprint layer 2-1 is located on the outermost side of the sensor and is the force-bearing surface that directly contacts the object being measured. Preferably, the biomimetic fingerprint layer 2-1 is made of a flexible polymer elastic material, and its surface forms concentric ring-shaped, arc-shaped, or fingerprint-like microstructures. Preferably, the thickness of the biomimetic fingerprint layer 2-1 is 50μm to 2mm, the height of the protrusions or the depth of the grooves of the surface microstructures is 5μm to 500μm, the spacing between adjacent protrusions is 20μm to 1000μm, and the width of a single ridge is 20μm to 800μm. When the microstructure is a concentric ring structure, the outer diameter of the concentric ring is 0.5mm to 15mm, and the number of ring protrusions is 2 to 20. When the microstructure is an arc-shaped or fingerprint-like structure, its radius of curvature, ridge spacing, and number of ridges can be adjusted according to the contact area, friction enhancement requirements, and processing precision.

[0027] The biomimetic fingerprint layer 2-1 serves two purposes: firstly, it increases the coefficient of friction between the sensor surface and the object being measured, reducing interface slippage under conditions such as grasping, pressing, and sliding, thus improving contact stability; secondly, the concave-convex microstructure can locally converge and guide external loads, enabling the contact force to be more effectively transmitted to the interlocked piezoelectric module 2-2 and the array capacitor module 2-4 below, enhancing the degree of local deformation of the internal sensitive structure, and improving the sensor's response to weak pressure, texture undulations, and changes in contact state.

[0028] like Figure 4 As shown, located below the bionic fingerprint layer 2-1 is the interlocked piezoelectric module 2-2. This interlocked piezoelectric module 2-2 includes an upper electrode layer 2-2-1, an upper piezoelectric sheet 2-2-2, a lower piezoelectric sheet 2-2-3, and a lower electrode layer 2-2-4. The upper electrode layer 2-2-1 is connected to the upper piezoelectric sheet 2-2-2, and the lower electrode layer 2-2-4 is connected to the lower piezoelectric sheet 2-2-3. It is used to collect the charge signal generated by the piezoelectric material under stress and connects to an external analysis circuit via leads. The upper electrode layer 2-2-1 and the lower electrode layer 2-2-4 are preferably made of silver nanowire material to form thin-film electrode layers. The upper piezoelectric sheet 2-2-2 and the lower piezoelectric sheet 2-2-3 are preferably made of PVDF piezoelectric material, which has advantages such as good flexibility, fast response speed, and suitability for fabricating flexible tactile sensors.

[0029] Furthermore, such as Figure 5 , Figure 6As shown, the upper piezoelectric sheet 2-2-2 and the lower piezoelectric sheet 2-2-3 are positioned opposite each other and form an interlocking meshing structure. Preferably, this interlocking meshing structure is an arched interlocking structure, that is, a set of spaced-apart protrusions are formed at the bottom of the upper piezoelectric sheet 2-2-2, and another set of corresponding protrusions are formed at the top of the lower piezoelectric sheet 2-2-3. The two sets of protrusions are initially spaced apart, but under pressure, they stagger and gradually mesh, forming an interlocking contact interface. Compared with ordinary planar multilayer piezoelectric structures, this arched interlocking structure can convert the externally applied normal pressure into a more significant transverse tensile component, causing the PVDF piezoelectric material to preferentially operate in the d31 transverse strain mode, while amplifying the effect of the force, thereby improving the piezoelectric output voltage and dynamic response sensitivity. Preferably, the thicknesses of the upper piezoelectric sheet 2-2-2 and the lower piezoelectric sheet 2-2-3 are 20 μm to 500 μm, respectively, and the thicknesses of the upper electrode layer 2-2-1 and the lower electrode layer 2-2-4 are 100 nm to 50 μm, respectively. For the arched or hemispherical protrusion unit, its radius of curvature is 50 μm to 2 mm, the protrusion height is 20 μm to 1 mm, the bottom width of the protrusion is 50 μm to 3 mm, and the center-to-center distance between adjacent protrusion units is 50 μm to 5 mm. The upper and lower protrusion units can be in contact in the initial state, or they can maintain an initial gap of 0 μm to 500 μm to adapt to different pressure detection ranges and sensitivity requirements.

[0030] When an external load first comes into contact or changes rapidly, the biomimetic fingerprint layer 2-1 first transmits the force to the interlocked piezoelectric module 2-2. The upper and lower interlocking structures approach and engage during the compression process, causing significant deformation, especially lateral stretching, in the upper piezoelectric sheet 2-2-2 and the lower piezoelectric sheet 2-2-3. Due to the piezoelectric effect, the piezoelectric material outputs a potential difference signal during this instantaneous force change. This potential difference signal can directly reflect the dynamic force information at the moment of contact, such as impact, knocking, transient pressing, and vibration; on the other hand, it can serve as a pre-trigger signal for the subsequent array capacitor module 2-4 to enter its working state. Therefore, the interlocked piezoelectric module 2-2 serves both as a dynamic tactile information detection function and as an event-driven entry point for triggering the downstream static detection module.

[0031] An insulating layer 2-3 is disposed below the interlocked piezoelectric module 2-2, between the interlocked piezoelectric module 2-2 and the array capacitor module 2-4, to achieve electrical isolation and mechanical transition between the upper and lower functional modules. Preferably, the insulating layer 2-3 is made of a flexible and insulating polymer thin-film material, and is bonded to the interlocked piezoelectric module 2-2 and the array capacitor module 2-4 respectively by a flexible adhesive material. The insulating layer 2-3 can effectively suppress crosstalk between the output signal of the interlocked piezoelectric module and the detection signal of the capacitor array, improving the signal stability, detection accuracy, and reusability of the entire sensor. Preferably, the thickness of the insulating layer 2-3 is 10μm to 1mm. The functional layers can be connected by a flexible adhesive layer with a thickness of 1μm to 200μm. Depending on the packaging method, adjacent functional layers can be bonded together or have a micro-gap of 0μm to 500μm reserved to meet the requirements of structural deformation, interlocking engagement, and signal isolation.

[0032] like Figure 7 As shown, the array capacitor module 2-4 is disposed below the insulating layer 2-3 for detecting continuous static force and spatial distribution information. The array capacitor module 2-4 includes an upper array electrode 2-4-1, a dielectric layer 2-4-2, and a lower array electrode 2-4-3. The upper array electrode 2-4-1 and the lower array electrode 2-4-3 each include a flexible substrate and an array of capacitor plates disposed on the flexible substrate. Preferably, the flexible substrate is made of PI material, which not only has good flexibility and mechanical stability but also high electrical insulation performance, facilitating the flexible integration and stable operation of the array electrodes. The array of capacitor plates are embedded in the flexible substrate and are preferably manufactured by curing and cutting with silver paste. The dielectric layer 2-4-2 is located between the upper array electrode 2-4-1 and the lower array electrode 2-4-3, and is preferably made of a flexible dielectric material such as PDMS, providing a compressible and deformable capacitor dielectric layer.

[0033] Furthermore, such as Figure 8 , Figure 9 and Figure 10As shown, the arrayed main plates on the upper array electrode 2-4-1 and the arrayed secondary plates on the lower array electrode 2-4-3 are arranged in a one-to-one correspondence, forming multiple independent or addressable capacitor units. Preferably, the array size of the capacitor units in the array capacitor module 2-4 is 2×2 to 64×64. The length of a single rectangular capacitor plate is 100μm to 10mm, the width is 100μm to 10mm, and the thickness is 100nm to 100μm; the spacing between adjacent capacitor plates is 20μm to 5mm. The thickness of the flexible substrate is 5μm to 500μm, and the thickness of the dielectric layer 2-4-2 is 10μm to 2mm. When the sensor is continuously pressurized, the pressure from the upper structure is transmitted to the array capacitor module 2-4 through the insulating layer 2-3, causing a change in the thickness of the local dielectric layer, which in turn changes the distance or facing area between some electrodes, thereby causing a change in the capacitance value of the corresponding capacitor unit.

[0034] The formula is determined by capacitance: In the formula, This is the capacitance value. The vacuum permittivity, The relative permittivity of the dielectric layer, This represents the initial area of ​​the electrodes facing each other. This represents the change in the area of ​​the electrode facing each other. The initial spacing between the electrodes. This represents the change in electrode spacing.

[0035] By collecting and analyzing the capacitance changes of each capacitor unit, it is possible to identify continuous static pressure, the location of force application, pressure distribution, and tangential action.

[0036] Specifically, when the external force is predominantly pressure with a normal component, the array capacitor module 2-4 mainly exhibits a decrease in the thickness of the dielectric layer 2-4-2 in the corresponding region, a shortening of the electrode spacing, and an increase in the capacitance value of the corresponding capacitor unit. Through a pre-established calibration relationship between capacitance change and pressure value, the measured capacitance change can be converted into the magnitude of continuous pressure. When an external force acts on a local area, one or more capacitor units closest to the force center will produce a more significant capacitance change. The contact position can be determined based on the region where the unit with the largest capacitance change is located or the weighted distribution of the changes in multiple units. When the external force includes a tangential component, the contact interface may cause relative slippage of the flexible electrode or displacement of the deformable structure, leading to changes in the facing area of ​​some capacitor units. By comparing the differences in changes in capacitor units in different regions of the array, the magnitude and direction of the tangential force can be further inferred.

[0037] In this embodiment, the interlocked piezoelectric module 2-2 and the array capacitor module 2-4 are not simply stacked side-by-side, but rather work in tandem through a "piezoelectric leader triggering, capacitor on-demand detection" mechanism. Specifically, when an external force is applied to the sensor surface, the interlocked piezoelectric module 2-2, due to its sensitivity to the rate of change of force, prioritizes outputting a transient trigger signal. After receiving this trigger signal, the control circuit then activates the array capacitor module 2-4 to perform array scanning and static detection. If the contact is brief, the system can record only the dynamic response results of the interlocked piezoelectric module; if the contact is continuous, the array capacitor module continues to operate, acquiring continuous pressure and its spatial distribution information. Thus, the traditional long-term continuous energization and periodic scanning mode of the capacitor array can be transformed into an on-demand detection mode based on contact events, reducing overall system power consumption and improving energy efficiency.

[0038] Specifically, during the detection process, when force is applied to the composite tactile sensor 2, the interlocked piezoelectric module 2-2 first senses the instantaneous change in the force signal and converts the mechanical stimulation into an electrical signal through the piezoelectric effect. This electrical signal enters the analysis circuit for dynamic pressure analysis, and the magnitude of the instantaneous dynamic force is calculated by combining the calibration relationship between the piezoelectric output voltage and the dynamic load. On the other hand, it serves as an enable signal to trigger the array capacitor module 2-4 to enter the working state. If the external force continues to exist, the array capacitor module 2-4 scans and samples the array capacitor units to obtain the capacitance change value of each unit. Based on the change in the electrode spacing or the change in the facing area reflected by the capacitance value change, combined with the structural parameters and material mechanical properties, the magnitude of the continuous static pressure, the location of the force-bearing area, and the force distribution state are further calculated.

[0039] Furthermore, the interlocked piezoelectric module 2-2 and the array capacitor module 2-4 complement each other functionally. The interlocked piezoelectric module 2-2 is mainly responsible for detecting mechanical information during the moment of contact establishment, rapid impact, vibration disturbance, and dynamic processes, and features fast response, high sensitivity, and no need for continuous power supply. The array capacitor module 2-4 is mainly responsible for static pressure measurement, pressure distribution analysis, and contact position identification during the contact holding phase, and is suitable for obtaining multi-point spatial information under stable contact conditions. Through the above composite design, the present invention can simultaneously meet the needs of dynamic force and static force detection, realize the fusion of position recognition and multi-dimensional tactile information, and is suitable for application scenarios such as robot dexterous grasping, intelligent prosthetic contact feedback, flexible electronic skin, and wearable interactive devices.

[0040] like Figure 11As shown, in this embodiment, the fabrication process of the composite tactile sensor includes the following steps: First, 3D printing molds for a biomimetic fingerprint structure, a piezoelectric sheet, and a flexible substrate is used to fabricate an interlocking piezoelectric module and an array capacitor module, respectively. After hot pressing and polarization treatment, a piezoelectric sheet with arched protrusions is obtained from PVDF material. Electrode layers are fabricated on its upper and lower surfaces, and wires are led out. Then, a biomimetic fingerprint layer is sequentially attached to the upper surface of the interlocking piezoelectric module, and an insulating layer is attached to the lower surface, completing the performance testing of the interlocking piezoelectric module. For the array capacitor module, PI material is first poured into a mold and cured. After demolding to obtain a flexible substrate, wires are led out, silver paste conductive electrodes are coated and cured, and cut to form array capacitor plates. These plates are then assembled with a PDMS dielectric layer and a flexible substrate, completing the performance testing of the array capacitor module. Finally, the qualified interlocking piezoelectric module and array capacitor module are packaged and integrated to obtain the piezoelectric-capacitive composite tactile sensor.

[0041] Example 2: Please refer to Figure 12 , Figure 13 and Figure 14 As shown, the difference between this embodiment and Embodiment 1 is that the interlocking piezoelectric module adopts a trapezoidal interlocking structure. Its principle is also the same: through the contact engagement of the upper and lower opposing protrusions, the normal compression is converted into a more pronounced lateral deformation to improve piezoelectric output performance. In Embodiment 2, when the interlocking structure is a trapezoidal interlocking structure, the height of the trapezoidal protrusion is 20μm to 1mm, the width of the upper base is 20μm to 2mm, the width of the lower base is 50μm to 3mm, and the center-to-center distance between adjacent trapezoidal protrusion units is 50μm to 5mm.

[0042] Example 3: Please refer to Figure 15 , Figure 16 As shown, the difference between this embodiment and Embodiment 1 is that the array capacitor module uses irregularly shaped plates to enhance its ability to identify changes in tangential force direction or complex force distribution. In Embodiment 3, when the array capacitor plates use irregularly shaped plates, the irregularly shaped plates may include comb-shaped, fan-shaped, arc-shaped, cross-shaped, asymmetrical polygonal, or combinations thereof. The maximum external length of the irregularly shaped plate is 100μm to 10mm, and the maximum external width is 100μm to 10mm; when the irregularly shaped plate is a comb-shaped structure, the tooth width is 10μm to 1mm, the tooth spacing is 10μm to 1mm, and the tooth length is 50μm to 5mm; when the irregularly shaped plate is a fan-shaped structure, its central angle is 10° to 180°, and its radial length is 100μm to 10mm. By setting asymmetrical or direction-sensitive plate shapes, the array capacitor module's ability to identify tangential force direction, slippage trend, and complex pressure distribution can be enhanced.

[0043] In the embodiments of the present invention, the materials, thickness parameters, number of array units, electrode size and arrangement, interlocking structure height and spacing, dielectric layer thickness, bonding method, and signal acquisition circuit configuration of each layer can be selected and adjusted according to the specific application scenario, sensitivity requirements, measurement range, power consumption constraints, and processing conditions. As long as the collaborative functions of dynamic force detection, energy-saving event trigger detection, static force detection, and position recognition described in the present invention can be achieved, they should all be considered to fall within the protection scope of the present invention.

[0044] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its scope and spirit, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A composite tactile sensor integrating an interlocking structure and an array of electrodes, characterized in that, The device includes, from top to bottom, a biomimetic fingerprint layer, an interlocking piezoelectric module, an insulating layer, and an array capacitor module. The surface of the biomimetic fingerprint layer is provided with concave and convex microstructures to increase the surface friction between the sensor and the object being measured and to enhance the deformation response of the internal piezoelectric material and capacitor plates. The interlocking piezoelectric module includes an interlocking upper piezoelectric component and a lower piezoelectric component. The insulating layer is a rectangular plate structure used to achieve electrical isolation between the interlocked piezoelectric module and the array capacitor module; the array capacitor module is an array-type capacitor detection structure, including an upper array electrode, a lower array electrode, and a dielectric layer disposed between the two. When an external force is continuously applied to the sensor, the interlocked piezoelectric module outputs a pre-triggered signal, and the array capacitor module is energized to detect the capacitance change of each array capacitor unit to characterize the magnitude of the continuous force, and to determine the position of the force based on the relative change relationship of each capacitor unit.

2. The composite tactile sensor integrating an interlocking structure and an array of electrodes according to claim 1, characterized in that, The convex-concave microstructure is one or more of the following: concentric ring, arc, or fingerprint-like. The convex height of the convex-concave microstructure is 5μm-500μm, the spacing between adjacent convex lines is 20μm-1000μm, and the width of a single line is 20μm-800μm.

3. The composite tactile sensor integrating an interlocking structure and an array of electrodes according to claim 1, characterized in that, The interlocking structure between the upper and lower piezoelectric components is an arched interlocking structure. The bottom of the upper piezoelectric component forms a set of spaced protrusions, and the top of the lower piezoelectric component has another set of protrusions that match the protrusions. The two sets of protrusions are staggered to form an interlocking contact interface.

4. A composite tactile sensor integrating an interlocking structure and an array of electrodes according to claim 1, characterized in that, The interlocking structure between the upper and lower piezoelectric components is a trapezoidal interlocking structure. The bottom of the upper piezoelectric component forms a set of spaced protrusions, and the top of the lower piezoelectric component has another set of protrusions that match the protrusions. The two sets of protrusions are staggered to form an interlocking contact interface.

5. A composite tactile sensor integrating an interlocking structure and an array of electrodes according to claim 1, characterized in that, The upper piezoelectric component includes an upper electrode layer and an upper piezoelectric sheet connected in sequence, and the lower piezoelectric component includes a lower electrode layer and a lower piezoelectric sheet connected in sequence. The thickness of the upper piezoelectric sheet and the lower piezoelectric sheet is 20μm-500μm, and the thickness of the upper electrode layer and the lower electrode layer is 100nm-50μm.

6. A composite tactile sensor integrating an interlocking structure and an array of electrodes according to claim 1, characterized in that, The insulating layer is made of a flexible and insulating polymer thin-film material, and the thickness of the insulating layer is 10μm-1mm.

7. A composite tactile sensor integrating an interlocking structure and an array of electrodes according to claim 1, characterized in that, The upper and lower array electrodes constitute multiple capacitor units, and the capacitance change value of each capacitor unit is used to characterize tactile information. By the capacitance change value and its spatial distribution, information such as the position of the point of application, the magnitude of pressure, the pressure distribution, and the direction of force are obtained. The magnitude of normal pressure is determined by the deformation caused by the force and the change in the distance between the plates. The position of the point of application of force is determined by the area where the unit with the largest capacitance change is located. The magnitude and direction of tangential force are characterized by the change in the area directly opposite the plates.

8. A composite tactile sensor integrating an interlocking structure and an array of electrodes according to claim 1, characterized in that, The upper array electrode and the lower array electrode each include a flexible substrate and an array of capacitor plates disposed on the flexible substrate. The flexible substrate is made of PI material.

9. A composite tactile sensor integrating an interlocking structure and an array of electrodes according to claim 8, characterized in that, The electrode plate shapes of the upper and lower array electrodes include rectangular, comb-shaped, fan-shaped, arc-shaped, cross-shaped, asymmetrical polygonal or combinations thereof, and the maximum external length of the upper and lower array electrodes is 100μm to 10mm, and the maximum external width is 100μm to 10mm.

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