Flexible tactile sensing system and wearable device

Abstract

This disclosure provides a flexible tactile sensing system and a wearable device. The flexible tactile sensing system includes electronic skin and a driving device. The electronic skin includes a piezoresistive functional layer and an electrode layer. The piezoresistive functional layer contacts an object to be grasped and detects the pressure of the grasped object, while the electrode layer contacts the skin of the hand. The driving device includes a control module and a current source module. The control module is electrically connected to the piezoresistive functional layer and the current source module. The control module receives the pressure signal from the piezoresistive functional layer and controls the current source module to output current to the electrode layer. The electronic skin also includes an insulating substrate layer. The piezoresistive functional layer includes multiple spaced pressure detection patches, and the electrode layer includes multiple spaced electrode patches. The pressure detection patches and electrode patches are arranged in pairs and are correspondingly distributed on two opposing surfaces of the insulating substrate layer. By amplifying and converting minute contact forces into multi-dimensional electrical stimulation signals, the patient's tactile feedback loop can be effectively reconstructed.

Description

Technical Field

[0001] This disclosure belongs to the field of flexible electronics and neurorehabilitation technology, specifically relating to a flexible tactile sensing system and wearable device. Background Technology

[0002] Tactile perception, as a fundamental dimension of human perception and interaction with the physical world, plays an irreplaceable role in fields such as precision medical assistance, high-performance robotic manipulation, and immersive virtual reality. Especially for patients with tactile dysfunction (such as tactile hyposensitivity) caused by nerve damage such as stroke, real-time and accurate tactile force feedback is crucial for rebuilding hand function and restoring natural interaction. However, existing electro-haptic feedback technologies still face many challenges in practical applications. First, most existing interfaces are limited to passively reproducing natural tactile signals, failing to fully utilize the high adjustability of electrical stimulation parameters to actively expand the human body's perceptual bandwidth, making it difficult to meet the high-resolution force perception requirements that exceed physiological limits in precision tasks. Second, in terms of hardware implementation, traditional drive systems are often bulky, and the feedback electrodes lack good skin compliance and flexibility, which not only limits the flexibility of natural hand movements but also hinders wearable integration of the system. Simultaneously, most solutions suffer from physical spatial misalignment between sensing and feedback points, causing users to bear a heavy cognitive burden of spatial remapping during interaction. Furthermore, existing sensor feedback arrays are mostly concentrated in localized areas such as the fingertips, resulting in small coverage areas and low sensing density, while neglecting the crucial role of the palm and knuckles in whole-hand coordinated interaction. In the field of rehabilitation, due to the lack of closed-loop intervention methods that can effectively integrate real-time environmental perception and personalized enhanced feedback, existing interface solutions are insufficient to achieve effective force perception reconstruction and fine grip force control for patients with tactile impairment.

[0003] Therefore, how to construct a tactile interface that integrates high-density perception, flexible integrated feedback, and perception enhancement algorithms has become a key issue that urgently needs to be addressed in the field of next-generation human-computer interaction. Summary of the Invention

[0004] Therefore, the purpose of this disclosure is to provide a flexible tactile sensing system and wearable device to at least solve one of the technical problems existing in the related art.

[0005] A first aspect of this disclosure provides a flexible tactile sensing system, comprising: an electronic skin, the electronic skin including a piezoresistive functional layer and an electrode layer, the piezoresistive functional layer contacting an object to be grasped and detecting the pressure of the grasped object, and the electrode layer contacting the skin of the hand; a driving device, the driving device including a control module and a current source module, the control module being electrically connected to the piezoresistive functional layer and the current source module, the control module receiving pressure signals from the piezoresistive functional layer and controlling the current source module to output current to the electrode layer; wherein, the electronic skin further includes an insulating substrate layer made of insulating material, the piezoresistive functional layer including a plurality of spaced pressure detection patches, and the electrode layer including a plurality of spaced electrode patches, the pressure detection patches and the electrode patches being arranged in pairs and correspondingly distributed on two opposing surfaces of the insulating substrate layer.

[0006] Furthermore, in some embodiments, the insulating substrate layer includes a first surface and a second surface that are opposite to each other, and the electronic skin further includes: two electrode conductive layers, one of which is disposed on the first surface and electrically connected to the piezoresistive functional layer and the driving device, and the other electrode conductive layer is disposed on the second surface and electrically connected to the electrode layer and the driving device.

[0007] Furthermore, in some embodiments, the electronic skin further includes: two encapsulation protective layers made of insulating material, the two encapsulation protective layers being respectively disposed on the side of the two electrode conductive layers away from the insulating substrate layer, wherein a first cutout is provided on one encapsulation protective layer at a position corresponding to the pressure detection piece to expose the pressure detection piece, and a second cutout is provided on the other encapsulation protective layer at a position corresponding to the electrode patch to expose the electrode patch.

[0008] Furthermore, in some embodiments, the piezoresistive functional layer includes at least one of carbon black, graphene, carbon nanotubes, graphite, carbon nanofibers, metal micro / nano powders / wires / sheets, MXene, liquid metal, PEDOT:PSS, polypyrrole, and polyaniline.

[0009] Furthermore, in some embodiments, the electrode conductive layer and the electrode layer are made of conductive materials, including at least one of silver paste, gold, copper, aluminum, carbon-based materials, metal nanowires, liquid metal, conductive polymers, and conductive hydrogels.

[0010] Furthermore, in some embodiments, the piezoresistive functional layer, the encapsulation protective layer, the electrode conductive layer, the insulating substrate layer, and the electrode layer are all made of flexible materials.

[0011] Furthermore, in some embodiments, the driving device further includes: a power supply module electrically connected to a current source module and a control module; and a communication module for communicating with a host computer.

[0012] Furthermore, in some embodiments, the flexible tactile sensing system further includes: a flexible cabling assembly connecting the driving device and the electronic skin, the flexible cabling assembly including a sensing flexible cabling and an electrode flexible cabling, the sensing flexible cabling being electrically connected to the piezoresistive functional layer, and the electrode flexible cabling being electrically connected to the electrode layer.

[0013] Furthermore, in some embodiments, a grounding node is provided on the driving device, and the flexible tactile sensing system further includes a common ground patch module connected to the grounding node of the driving device. The common ground patch module is used to contact the user's skin to form a circuit with the electrode layer to achieve electrical stimulation.

[0014] A second aspect of this disclosure provides a wearable device, including a flexible tactile sensing system as described in any of the first aspects of this disclosure.

[0015] The flexible tactile sensing system provided in this embodiment includes electronic skin and a driving device. The electronic skin includes a piezoresistive functional layer and an electrode layer. The piezoresistive functional layer can detect the pressure of the hand grasping an object. The driving device can convert the pressure into a perceptible current signal and transmit it to the electrode layer. The electrode layer then transmits electrical stimulation to the user's hand, thereby providing real-time tactile feedback and improving the user's force perception ability. This is especially suitable for people whose hand tactile sensation is dulled or deteriorated due to neurological diseases. Furthermore, multiple pressure detection pads are distributed on the first surface of the insulating substrate layer, and multiple electrode patches are distributed on the second surface of the insulating substrate layer opposite to the first surface. The multiple pressure detection pads and multiple electrode patches are arranged in pairs, one-to-one, so that when the user's hand performs actions such as grasping or pinching, the location where the pressure is detected is approximately the same as the location where the current stimulation is received. Thus, the flexible tactile sensing system can provide more accurate real-time tactile feedback, improve the user's force perception ability, enhance the perceived intensity of grasping and pinching actions, and thus more accurately control hand movements.

[0016] The flexible tactile sensing system provided in this embodiment converts the pressure detected by the piezoresistive functional layer into an electric current emitted by the electrode layer, and the stimulation of the current is directly applied to the skin of the human hand; weak force corresponds to weak electrical stimulation, and strong force corresponds to strong electrical stimulation. Specifically, the flexible tactile sensing system provided in this embodiment can amplify the perception of small forces on a human. For example, it is difficult for a person to feel the difference between a force of 0.5N and 0.6N, but they can feel the difference between a current of 1mA and 1.5mA. The flexible tactile sensing system provided in this embodiment amplifies the user's perception of force within a small force range through current stimulation.

[0017] The flexible tactile sensing system provided in this embodiment is particularly suitable for stroke patients with reduced tactile sensation. By amplifying minute contact forces and converting them into multidimensional electrical stimulation signals, the system can effectively reconstruct the patient's tactile feedback loop, correct their "over-gripping" behavior caused by insufficient perception, and prevent objects from being damaged or slipping.

[0018] Further aspects and / or advantages of the general concept of this disclosure will be set forth in part in the description which follows, and in part will be clear from the description or may be learned by practice of the general concept of this disclosure. Attached Figure Description

[0019] The above and other objects and features of this disclosure will become clearer from the following description of embodiments in conjunction with the accompanying drawings, in which: Figure 1 A schematic diagram of the structure of an electronic skin according to an embodiment of the present disclosure is shown; Figure 2 A block diagram of a flexible tactile sensing system according to an embodiment of the present disclosure is shown; Figure 3 A graph of a two-parameter mapping function of current amplitude versus frequency according to an embodiment of the present disclosure is shown. Figure 4 A schematic diagram illustrating an embodiment of the present disclosure shows independently adjustable frequency, duty cycle, and amplitude; Figure 5 A schematic diagram of an electronic skin and a partial structure adhered to the skin according to an embodiment of the present disclosure is shown; Figure 6 A schematic diagram of the connection structure between the electronic skin and the flexible cable assembly according to an embodiment of the present disclosure is shown; Figure 7 A partial structural schematic diagram of a flexible cabling assembly according to an embodiment of the present disclosure is shown; Figure 8 A schematic diagram of the structure of an electronic skin according to an embodiment of the present disclosure is shown; Figure 9 A schematic diagram of the structure of a wearable device according to an embodiment of the present disclosure is shown; Figure 10 A partial structural schematic diagram of a wearable device according to an embodiment of the present disclosure is shown.

[0020] Explanation of icon numbers: 10 - Electronic skin, 110 - Piezoresistive functional layer, 120 - Electrode layer, 130 - Insulating substrate layer, 140 - Electrode conductive layer, 150 - Encapsulation protective layer, 151 - First cutout, 152 - Second cutout, 20 - Driving device, 210 - Control module, 220 - Current source module, 221 - High voltage multiplexer, 222 - Bidirectional current source, 223 - Operational amplifier, 224 - Digital-to-analog converter, 230 - Transmission Sensing module, 231-Analog-to-Digital Converter, 232-Multiple-Channel Selector, 240-Power Module, 241-Power Supply Unit, 242-12V Busbar, 243-High Voltage Busbar, 244-3.3V Busbar, 250-Communication Module, 251-Bluetooth, 252-Serial Port, 30-Flexible Cable Assembly, 310-Sensing Flexible Cable, 320-Electrode Flexible Cable, 40-Common Ground Patch Module, 50-Housing, 60-Watch Strap. Detailed Implementation

[0021] The following detailed embodiments are provided to aid the reader in gaining a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will become apparent upon understanding this disclosure. For example, the order of operations described herein is merely illustrative and is not limited to those orders set forth herein, but may be changed as will become clear upon understanding this disclosure, except for operations that must occur in a specific order. Furthermore, for clarity and conciseness, descriptions of features known in the art may be omitted.

[0022] The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein, which will become clear upon understanding the disclosure of this application.

[0023] As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more.

[0024] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts should not be limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Thus, without departing from the teaching of the examples described herein, the first component, first assembly, first region, first layer, or first part referred to as the first component, first assembly, first region, first layer, or first part may also be referred to as the second component, second assembly, second region, second layer, or second part.

[0025] In the specification, when an element such as a layer, region, or substrate is described as being "on" another element, "connected to," or "bonded to" another element, the element may be directly "on" another element, directly "connected to," or "bonded to" the other element, or one or more other elements may be present in between. Conversely, when an element is described as being "directly on" another element, "directly connected to," or "directly bonded to" another element, no other elements may be present in between.

[0026] The terminology used herein is for the purpose of describing various examples only and is not intended to limit disclosure. Unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. The terms “comprising,” “including,” and “having” indicate the presence of the described features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof. The term “a plurality” represents any quantity of two or more.

[0027] The directional terms such as "upper," "lower," "left," "right," "top," and "bottom" used in this application are based on the orientation shown in the accompanying drawings and are used only for the convenience of description. They are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0028] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains upon understanding this disclosure. Unless expressly defined herein, terms such as those defined in a general dictionary shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field and in this disclosure, and shall not be interpreted in an idealized or overly formalistic manner.

[0029] The following will combine Figures 1 to 10 This disclosure introduces a flexible tactile sensing system and wearable device provided by embodiments thereof.

[0030] like Figure 1 , Figure 2 , Figure 6 and Figure 8As shown, a first aspect of this disclosure provides a flexible tactile sensing system, comprising: an electronic skin 10, the electronic skin 10 including a piezoresistive functional layer 110 and an electrode layer 120, the piezoresistive functional layer 110 contacting an object to be grasped and detecting the pressure of grasping the object, and the electrode layer 120 contacting the skin of the hand; a driving device 20, the driving device 20 including a control module 210 and a current source module 220, the control module 210 being electrically connected to the piezoresistive functional layer 110 and the current source module 220, the control module 210 receiving the pressure signal from the piezoresistive functional layer 110 and controlling the current source module 220 to output current to the electrode layer 120; wherein, the electronic skin 10 further includes an insulating substrate layer 130 made of insulating material, the piezoresistive functional layer 110 including a plurality of spaced pressure detection patches, and the electrode layer 120 including a plurality of spaced electrode patches, the pressure detection patches and the electrode patches being arranged in pairs and correspondingly distributed on two opposing surfaces of the insulating substrate layer 130.

[0031] The flexible tactile sensing system provided in this embodiment includes an electronic skin 10 and a driving device 20. The electronic skin 10 includes a piezoresistive functional layer 110 and an electrode layer 120. The piezoresistive functional layer 110 can detect the pressure of the palm gripping an object. The driving device 20 can convert the pressure into a perceptible current signal and transmit it to the electrode layer 120. The electrode layer 120 transmits electrical stimulation to the user's hand, thereby providing real-time tactile feedback and improving the user's force perception ability. It is especially suitable for people whose hand tactile sensation is dulled or deteriorated due to neurological diseases. Furthermore, multiple pressure detection pads are distributed on the first surface of the insulating substrate 130, and multiple electrode patches are distributed on the second surface of the insulating substrate 130 opposite to the first surface. The multiple pressure detection pads and multiple electrode patches are arranged in pairs, one-to-one correspondence, so that when the user's hand performs actions such as grasping or pinching, the location where pressure is detected is approximately the same as the location where current stimulation is received. Thus, the flexible tactile sensing system can provide more accurate real-time tactile feedback, improve the user's force perception ability, enhance the perception of the intensity of grasping and pinching actions, and thus more accurately control hand movements.

[0032] The flexible tactile sensing system provided in this embodiment converts the pressure detected by the piezoresistive functional layer 110 into an electric current emitted by the electrode layer 120, which directly stimulates the skin of the human hand. Weak force corresponds to weak electrical stimulation, and strong force corresponds to strong electrical stimulation. Specifically, the flexible tactile sensing system provided in this embodiment can amplify the perception of minute forces. For example, it is difficult for a person to perceive the difference between a 0.5N force and a 0.6N force, but they can perceive the difference between a 1mA current and a 1.5mA current. The flexible tactile sensing system provided in this embodiment amplifies the user's perception of force within a minute force range through electric current stimulation.

[0033] Furthermore, the electrode layer 120 is made of a conductive material, specifically at least one of the following: silver paste, gold, copper, aluminum, carbon-based materials, metal nanowires, liquid metal, conductive polymers, and conductive hydrogels. When the electrode layer 120 comes into contact with human skin, it reduces contact resistance. Specifically, the outermost layer of skin is the stratum corneum, which has low water content and extremely high resistance, making it the primary source of resistance. The electrode layer 120 is made of conductive hydrogel, which, upon contact with the skin, not only wets the skin and reduces the resistance of the stratum corneum but also increases the contact area with the skin, establishing effective contact.

[0034] Furthermore, the piezoresistive functional layer 110 includes at least one of carbon black, graphene, carbon nanotubes, graphite, carbon nanofibers, metal micro / nano powders / wires / sheets, MXene, liquid metal, PEDOT:PSS (poly(3,4-ethylenedioxythiophene)), polypyrrole, and polyaniline. It can convert external pressure or stress into a measurable change in resistance. The aforementioned materials have advantages such as high piezoresistive coefficient, high sensitivity, and fast response speed.

[0035] In other embodiments, the piezoresistive functional layer 110 may also be a piezoresistive composite composed of at least one material selected from carbon black, graphene, carbon nanotubes, graphite, carbon nanofibers, metal micro / nano powders / wires / sheets, MXene, liquid metal, PEDOT:PSS (full name poly-3,4-ethylenedioxythiophene), polypyrrole, and polyaniline loaded in a polymer matrix. The polymer matrix is ​​selected from PDMS, Ecoflex, Dragon Skin, silicone, polyurethane, SEBS, acrylic resin, polyimide resin, or epoxy resin. Preferably, the piezoresistive composite has a porous morphology, a three-dimensional surface microstructure, or a combination of both. The porous morphology can increase the deformation space, enhance the contact effect, and thus improve the sensitivity.

[0036] Furthermore, in some embodiments, as an example, such as Figure 1 , Figure 6 and Figure 8 As shown, multiple pressure detection pads and electrode patches are arranged at intervals on the user's fingers and palms, forming a distributed layout that covers the fingers and palms. This multi-point distribution coverage can accurately locate different parts of the hand, enabling simultaneous action in multiple areas of the hand, comprehensively covering the hand muscles and nerves, and achieving zoned stimulation or zoned detection to adapt to the user's different hand movement needs.

[0037] Furthermore, such as Figure 1 , Figure 6 and Figure 8As shown, at least one pressure detection pad and one electrode patch are distributed on each finger to achieve independent stimulation of each finger. When multiple pressure detection pads and electrode patches are distributed on a finger, for example, three to four pressure detection pads are distributed on each finger, and the number of electrode patches is the same as the number of pressure detection pads. The multiple pressure detection pads and electrode patches are arranged at intervals along the length of the finger, which makes the coverage area of ​​the detection points and stimulation points wider, reduces the mutual interference between adjacent pressure detection pads, and reduces the mutual interference between adjacent electrode patches, thereby improving local fine motor skills.

[0038] Furthermore, such as Figure 1 , Figure 6 and Figure 8 As shown, multiple pressure detection pads and motor pads are distributed on the palm. As an example, optionally, multiple pressure detection pads are distributed at the end of the palm away from the fingers and spaced apart, so that the sensing points and feedback points are distributed and covered at multiple points on the palm, which can realize the synchronous function of multiple areas of the palm and adapt to the different hand movement needs of users.

[0039] As an example, optionally, the number of pressure detection pads is 10 to 35, for example, it can be further reduced to 20 to 25, such as including but not limited to 20, 21, and 25; the number of electrode patches is the same as that of pressure detection pads, and they are set in pairs; this setting can avoid the problems of too many pressure detection pads and electrode patches, which would lead to overly dense arrangement, mutual interference of signals, complicated wiring, and a significant increase in manufacturing costs and assembly difficulty; on the other hand, it can avoid the problems of too few pressure detection pads and electrode patches, which would result in insufficient coverage, sparse stimulation points, and inability to achieve comprehensive and uniform electrical stimulation of the fingers and palms.

[0040] Furthermore, both the pressure detection pad and the electrode patch are individual thin sheets, with shapes including but not limited to circles, quadrilaterals, pentagons, etc.

[0041] Regarding the specific structure of the electronic skin 10, further, in some embodiments, such as Figure 1 As shown, the insulating substrate layer 130 includes a first surface and a second surface that are opposite to each other. The electronic skin 10 also includes two electrode conductive layers 140, one of which is disposed on the first surface and electrically connected to the piezoresistive functional layer 110 and the driving device 20, and the other electrode conductive layer 140 is disposed on the second surface and electrically connected to the electrode layer 120 and the driving device 20.

[0042] In these embodiments, conductive lines are distributed on the electrode conductive layer 140, which ensures that current can be transmitted efficiently and stably inside the electrode and between the electrode and external circuits, thereby ensuring the smooth progress of the current conduction process. Specifically, the electronic skin 10 includes two electrode conductive layers 140. One electrode conductive layer 140 is electrically connected to the piezoresistive functional layer 110 and the driving device 20, so that the pressure signal detected by the piezoresistive functional layer 110 can be transmitted to the control module 210 of the driving device 20 via the electrode conductive layer 140. The other electrode conductive layer 140 is electrically connected to the electrode layer 120 and the driving device 20, so that the current generated by the current source module 220 of the driving device 20 can be transmitted to the electrode layer 120, thereby providing electrical stimulation to the user.

[0043] Furthermore, in some embodiments, the electrode conductive layer 140 is made of a conductive material, including at least one of silver paste, gold, copper, aluminum, carbon-based materials, metal nanowires, liquid metal, conductive polymers, and conductive hydrogels.

[0044] Furthermore, in some embodiments, such as Figure 1 As shown, the electronic skin 10 also includes two encapsulation protective layers 150 made of insulating material. The two encapsulation protective layers 150 are respectively disposed on the side of the two electrode conductive layers 140 away from the insulating base layer 130. A first cutout portion 151 is provided on one encapsulation protective layer 150 at a position corresponding to the pressure detection piece to expose the pressure detection piece. A second cutout portion 152 is provided on the other encapsulation protective layer 150 at a position corresponding to the electrode patch to expose the electrode patch.

[0045] In these embodiments, the encapsulation protective layer 150 can prevent the electrode conductive layer 140 from being damaged by external environments such as mechanical damage, dust, moisture, and chemical corrosion, and avoid the circuits arranged in the electrode conductive layer 140 from being corroded or short-circuited. Furthermore, in order to allow the piezoresistive functional layer 110 and the electrode layer 120 to contact the outside world, a first cutout portion 151 is provided on the encapsulation protective layer 150 at a position corresponding to the pressure detection piece, exposing the pressure detection piece. This allows the pressure detection piece to directly contact the object when the user grasps it, thus improving pressure detection. A second cutout portion 152 is provided on the encapsulation protective layer 150 at a position corresponding to the electrode patch, exposing the electrode patch. This allows the current stimulation emitted by the electrode patch to directly act on the user's hand, achieving direct stimulation.

[0046] As an example, the first cutout portion 151 and the second cutout portion 152 can be formed by a cutout process such as drilling, cutting or penetrating engraving on the encapsulation protective layer 150.

[0047] Furthermore, in some embodiments, the piezoresistive functional layer 110, the encapsulation protective layer 150, the electrode conductive layer 140, the insulating substrate layer 130, and the electrode layer 120 are all made of flexible materials. This configuration allows the electronic skin 10 to conform to the curvature of the palm after being placed against it, without affecting the free movement of the fingers, thereby enabling more precise control of hand movements.

[0048] Furthermore, in some embodiments, such as Figure 2 As shown, the drive device 20 also includes a power supply module 240, which is electrically connected to the current source module 220 and the control module 210.

[0049] In these embodiments, the power module 240 can supply power to other modules in the drive device 20, such as the current source module 220, the control module 210, etc. Specifically, the power module 240 includes a power supply device 241, for example, such as... Figure 2 As shown, a lithium battery or a 5V serial port is selected as the power supply device 241. The power module 240 also includes a two-stage boost circuit. The two-stage boost circuit first boosts the input 5V supply voltage to 12V and forms a 12V bus 242. Then, the voltage of the 12V bus 242 is further boosted to 90V-120V and forms a high-voltage bus 243. The high-voltage bus 243 supplies power to the current source module 220, and the 12V bus 242 supplies power to the subsequent 90V-120V boost power supply circuit. This embodiment uses a two-stage boost structure of 5V→12V→90V, instead of directly boosting 5V to 90V, which can effectively reduce the output power supply ripple. The power module 240 also includes a buck module to reduce the supply voltage to 3.3V and / or 1.65V to supply power to digital circuits such as microcontrollers. Figure 2 As shown, in this embodiment, the 5V power supply voltage is reduced to 3.3V and a 3.3V bus 244 is formed.

[0050] Furthermore, in some embodiments, such as Figure 2 As shown, the drive device 20 also includes a communication module 250 for communicating with a host computer. The communication module 250 includes two communication modes: Bluetooth 251 and serial port 252, for communicating with the host computer to realize data transmission and communication connection between the wearable device and the host computer (e.g., mobile phone, computer, etc.), and acts as a bridge for interaction between hardware devices and networks or other devices.

[0051] Furthermore, in some embodiments, the current source module 220 can generate an independently adjustable current output in terms of amplitude, frequency, and duty cycle. This configuration allows the current output of the current source module 220 to be flexibly adjustable, enabling precise matching of different stimulation thresholds to meet the needs of different users and enhancing safety. Moreover, since all three parameters are independently adjustable and do not interfere with each other, a single parameter can be optimized to quickly select the most effective stimulation combination, improving the targeting of the stimulation.

[0052] Specifically, the amplitude is independently adjustable, allowing for flexible control of the current intensity based on skin impedance, nerve sensitivity, and stimulation site. This ensures effective stimulation while avoiding overcurrent that could cause burns, stinging, or excessive muscle spasms, thus enhancing safety for users. The frequency is also independently adjustable, allowing different frequencies to act on sensory and motor nerves respectively, achieving different effects such as analgesia, relaxation, and activation. The adjustable duty cycle controls the current conduction / interruption time, preventing skin polarization and electrolytic damage caused by continuous DC stimulation. Simultaneously, it simulates the natural pulse discharge patterns of human nerves, resulting in more natural stimulation and better tolerance. For example, such as... Figure 2 As shown, the current source module 220 includes a high-voltage multiplexer 221, a bidirectional current source 222, an operational amplifier 223, and a digital-to-analog converter 224. The high-voltage multiplexer 221 is electrically connected to multiple electrode patches. The positive and negative currents output by the bidirectional current source 222 can be arbitrarily distributed to different electrode patches through the high-voltage multiplexer 221, realizing bidirectional stimulation of different areas and different electrode patches, and adapting to large-area muscle / nerve stimulation. Furthermore, the current source module 220 outputs a constant current, so even if the human skin impedance changes with sweating, pressure, and contact position, the actual stimulation current remains stable, avoiding the stimulation intensity fluctuating in voltage source mode and ensuring stimulation consistency.

[0053] The current source module 220 receives the voltage output from the control module 210, thereby adjusting the magnitude of the output current. The current source module 220 includes a high-voltage multiplexer 221, which independently controls the current parameters of each channel, thereby enabling each electrode patch to be connected to an independent channel and achieve independent control.

[0054] Specifically, the current source module 220 adopts the Howland current source topology. The Howland current source is a voltage-controlled current source topology. Within the rated load impedance range, its output current is determined only by the input voltage and does not change with the load impedance (for example, an input voltage of 1V can output 1mA current, an input voltage of 2V can output 2mA current, and the output current will not change due to the load being 10kΩ or 1kΩ).

[0055] Furthermore, the embodiments of this aspect can achieve independent adjustment of amplitude, frequency, and duty cycle. The output current amplitude can be adjusted by changing the magnitude of the input control voltage; the frequency can be adjusted by controlling the output period of the current pulse, for example, when the pulse period is set to 10ms, the corresponding output frequency is 100Hz; while keeping the period unchanged, the duty cycle can be adjusted by adjusting the conduction duration of a single current pulse, for example, when the period is kept constant at 10ms, current pulses with conduction durations of 500μs and 200μs can be output respectively, thereby changing the duty cycle.

[0056] Furthermore, such as Figure 2 and Figure 5 As shown, the current source module 220 includes a bidirectional current source 222, which can output current in both forward and reverse directions. The direction is controllable, and the bidirectional output mode can effectively eliminate the polarization reaction of human skin, thereby improving the safety and comfort of electrical stimulation. Figure 5 The diagram above shows the current flowing in the forward direction, passing through the motor patch to the nerves in the user's hand, thus stimulating the user's hand; Figure 5 The diagram below illustrates the current flowing in the reverse direction, passing through the nerves in the user's hand to the motor patch.

[0057] The drive unit 20 also includes a sensing module 230, which employs a channel-selective voltage divider acquisition topology. This allows the module to selectively receive the resistance value of each pressure sensor, thereby enabling more precise pressure detection by zone. For example, Figure 2 As shown, the sensing module 230 includes a multiplexer 232 and an analog-to-digital converter 231.

[0058] Furthermore, in some embodiments, such as Figure 6 and Figure 7 As shown, the flexible tactile sensing system also includes a flexible cabling assembly 30, which connects the driving device 20 and the electronic skin 10. The flexible cabling assembly 30 includes a sensing flexible cabling 310 and an electrode flexible cabling 320. The sensing flexible cabling 310 is electrically connected to the piezoresistive functional layer 110, and the electrode flexible cabling 320 is electrically connected to the electrode layer 120.

[0059] In these embodiments, the flexible cable assembly 30 is bendable, resulting in better adaptability of the flexible structure, improved wearing comfort, and better suitability for bending requirements in flexible wearable scenarios. Furthermore, in this embodiment, the piezoresistive functional layer 110 and the electrode layer 120 are each independently connected to the driving device 20 via flexible cables. The sensing flexible cable 310 corresponding to the piezoresistive functional layer 110 is used to transmit weak pressure detection signals, while the electrode flexible cable 320 corresponding to the electrode layer 120 is used to transmit high-voltage bidirectional stimulation current signals. The two are physically and electrically isolated, effectively avoiding electromagnetic interference from the high-voltage stimulation signal to the pressure sensing signal. Simultaneously, the independent cables enable independent control of stimulation output and pressure detection, improving system stability and safety.

[0060] Furthermore, the flexible cabling assembly 30 uses an FPCB (flexible printed circuit board); among which, the sensing FPCB connected to the piezoresistive functional layer 110 adopts a row-column orthogonal cross-addressing architecture, with row and column select lines respectively arranged on different layers of the sensing FPCB, and electrical layer switching is achieved through through-layer vias at the intersection of their projections, thereby guiding them to the surface of the functional layer to form an array of piezoresistive sensing contacts, which can achieve multi-point pressure scanning detection with a significant reduction in the number of traces; the electrode FPCB connected to the electrode layer 120 adopts an independent channel design, with each electrode patch connected to the back-end high-voltage multiplexer 221 through an independent electrode FPCB channel.

[0061] Furthermore, in some embodiments, a grounding node is provided on the driving device 20, and the flexible tactile sensing system further includes a common ground patch module 40, which is connected to the grounding node of the driving device 20. The common ground patch module 40 is used to contact the user's skin to form a circuit with the electrode layer 120 to realize electrical stimulation.

[0062] In these embodiments, the common ground patch module 40 is electrically connected to the grounding node of the drive device 20. During use, it is attached to the user's skin surface, forming a complete human body current loop with the stimulation electrodes of the electrode layer 120. Specifically, the multiple stimulation electrodes of the electrode layer 120 output forward or reverse bidirectional stimulation current under the control of the high-voltage multiplexer 221. After being conducted through the skin, the current flows back from the common ground patch module 40 to the grounding node of the drive device 20, thus forming a closed electrical stimulation loop. The common ground patch module 40 ensures stable bidirectional current flow, providing a unified return path for the bidirectional stimulation current and avoiding current disturbances and loop errors when multiple stimulation electrodes work simultaneously. As the return electrode for the bidirectional stimulation current, the common ground patch module 40 forms a closed current loop with the stimulation electrodes of the electrode layer 120, thereby achieving stable and safe human body electrical stimulation.

[0063] The following describes the pressure-touch mapping method implemented using the flexible tactile sensing system provided in the embodiments of this aspect.

[0064] The pressure detected by multiple pressure sensors is divided into different segments, and each segment corresponds to a different current frequency; that is, the pressure is divided into several ranges (light pressure, medium pressure, heavy pressure), and each pressure level corresponds to a fixed electrical stimulation frequency. For example: light pressure → 50Hz, medium pressure → 100Hz, heavy pressure → 200Hz, the frequency only changes with the pressure range.

[0065] In one embodiment of this disclosure, the pressure is divided equally, but it may not be divided equally. It can be segmented according to the desired effect. For example, if more attention needs to be paid to the feedback effect of low contact force, the low force range can be divided into several segments.

[0066] It is understandable that, such as Figure 4 As shown, Figure 4 A schematic diagram illustrating an embodiment of the present disclosure shows independently adjustable frequency, duty cycle, and amplitude; Figure 4 The vertical axis represents the output current (mA), and the horizontal axis represents time (ms). Figure 4 From left to right, light blue, green, purple, and dark blue lines represent four different sets of frequencies (f), duty cycles (D), and amplitudes (Im). Specifically, the light blue line corresponds to an amplitude of Im = 2mA, a duty cycle of D = 2.5%, and a frequency of f = 100Hz; the green line corresponds to an amplitude of Im = 3mA, a duty cycle of D = 2.5%, and a frequency of f = 100Hz; the purple line corresponds to an amplitude of Im = 3mA, a duty cycle of D = 1%, and a frequency of f = 40Hz; and the blue line corresponds to an amplitude of Im = 3mA, a duty cycle of D = 2.5%, and a frequency of f = 40Hz.

[0067] Mapping current amplitude to pressure, including but not limited to linear, quadratic, cubic, and exponential mapping methods, can enhance the user's force perception.

[0068] Specifically, within the same pressure level, the greater the pressure, the greater the amplitude of the stimulation current. Linear, quadratic, cubic, and exponential curves can be used to simulate the feel of real skin. Ultimately, this achieves a high frequency and high current stimulation under high pressure, and a low frequency and low current stimulation under low pressure. By using both frequency and amplitude as dimensions, users can more clearly distinguish the intensity and enhance their ability to perceive force.

[0069] Among them, mapping refers to the mathematical relationship between the pressure magnitude and the amplitude of the stimulation current. The greater the pressure, the greater the current. Different mappings determine the rate at which the current increases with pressure, and are used to simulate different real tactile sensations.

[0070] In this embodiment, the mapping relationship between current amplitude and pressure is understood as follows: Linear mapping: The current amplitude changes uniformly in a direct proportion to the pressure, and the pressure change and the current change maintain a fixed proportional relationship, achieving smooth and linear force feedback.

[0071] Secondary mapping: The current amplitude increases quadratically with pressure. The greater the pressure, the faster the current amplitude increases, which can amplify the tactile resolution in the medium pressure range.

[0072] Triple mapping: The current amplitude increases cubically with pressure, further enhancing the sensitivity to pressure changes and strengthening tactile feedback under heavy pressure.

[0073] Exponential mapping: The current amplitude changes exponentially with pressure, which conforms to the natural sensory characteristics of human skin. Under slight pressure, the current changes slowly, while under heavy pressure, the current increases rapidly, which is consistent with the laws of real tactile perception.

[0074] The following describes the pressure-touch mapping method implemented using the flexible tactile sensing system provided in the embodiments of this aspect.

[0075] like Figure 3 As shown below, the method of implementing pressure-touch mapping in a flexible tactile sensing system will be explained using a secondary mapping as an example.

[0076] like Figure 3 As shown, I is the current intensity, and F is the pressure detected by the sensor; and These are the lower and upper limits of the user's electrical stimulation threshold at the corresponding frequency, respectively. and These are the lower and upper limits of the pressure sensing element (pressure sensor) range, respectively.

[0077] Where Imin is the user's corresponding Hertz ( Figure 3 The lower limit of current intensity at 100Hz (where I is the minimum current intensity at which a sensation is produced) is the current intensity at which the user feels a sensation; Imax is the current intensity at the corresponding hertz (where I is the minimum current intensity at which a sensation is produced). Figure 3 The upper limit of the current intensity that can be felt at 20Hz (i.e., the current intensity at which pain is felt).

[0078] This embodiment uses a quadratic polynomial mapping relationship to convert pressure into electrical stimulation current amplitude, and its mathematical expression is:

[0079] In the formula, I is the amplitude of the output electrical stimulation current, F is the pressure value collected by the piezoresistive functional layer 110, and K0, K1, and K2 are calibration coefficients.

[0080] This quadratic mapping relationship causes the current amplitude to increase non-linearly with pressure. Under slight pressure, the current changes slowly, while under heavy pressure, the current increases rapidly, which conforms to the natural tactile perception of human skin.

[0081] The coefficients K1 and K2 can be individually calibrated using the following formula:

[0082]

[0083] By collecting the current parameters corresponding to the reference pressure, tactile adaptation can be achieved for different users, improving the personalization and accuracy of force perception.

[0084] It is understood that in this embodiment, in order to achieve rapid personalized calibration, the calculation relationship of calibration coefficients K1 and K2 is specially set; this set of relationships is a special setting adapted to the tactile perception effect, and the coefficients can be adjusted according to different perception needs.

[0085] The following describes a method for implementing pressure-touch mapping in a flexible tactile sensing system, using a specific embodiment of this disclosure.

[0086] Before wearing wearable devices, a personalized calibration process must be completed. Specifically, before the system runs, the user's physiological thresholds must be obtained.

[0087] The current was gradually increased at different frequencies, and the faint current felt by the user was recorded. Record the electrical currents that cause discomfort . To transfer current Substituting these two parameters into the mapping formula ensures that the electrical stimulation is always within a safe and effective dynamic range.

[0088] The working cycle of a flexible tactile sensing system: Sensing stage: Piezoresistive functional layer 110 senses the pressure signal of the finger contacting the object in real time.

[0089] Processing stage: The drive unit 20 receives the signal and calculates the corresponding current amplitude and frequency based on the current frequency and the mapping relationship between current amplitude and pressure.

[0090] Feedback phase: The high voltage multiplexer 221 of the current source module 220 sends electrical pulses to the corresponding multiple electrode patches in a time-slice allocation manner.

[0091] Motion adjustment: Users adjust their grip strength in real time based on enhanced electrotactile feedback.

[0092] The flexible tactile sensing system provided in this embodiment is particularly suitable for stroke patients with reduced tactile sensation. By amplifying minute contact forces and converting them into multidimensional electrical stimulation signals, the system can effectively reconstruct the patient's tactile feedback loop, correct their "over-gripping" behavior caused by insufficient perception, and prevent objects from being damaged or slipping.

[0093] like Figure 9 and Figure 10 As shown, a second aspect of this disclosure provides a wearable device, including a flexible tactile sensing system as described in any of the above embodiments.

[0094] The wearable device provided in the embodiments of this aspect has the beneficial effects of any of the above embodiments due to having the flexible tactile sensing system provided in any of the above embodiments, which will not be described in detail here.

[0095] Furthermore, in some embodiments, such as Figure 9 and Figure 10 As shown, the wearable device includes a housing 50 and a strap 60. A mounting cavity is formed in the housing 50, and a drive unit 20 is disposed in the mounting cavity.

[0096] Furthermore, such as Figure 9 and Figure 10 As shown, when worn, the electronic skin 10 is attached to the palm side (palm surface), and the common patch module 40 is attached to the back side (back of the hand), forming a complete electrical stimulation circuit with the electrode layer 120 attached to the palm side. The driving device 20 includes a circuit board and is housed in the housing 50, and is worn on the wrist via the strap 60. The driving device 20 and the electronic skin 10 are connected via a flexible ribbon cable assembly 30.

[0097] The wearable device provided in this embodiment integrates a high-density sensing and feedback unit on a flexible electronic skin 10 to achieve full-hand electrotactile feedback, miniaturizes the stimulation source for portability and wearability, and detects external interactive pressure and feeds it back to the user through a method of mapping light tactile pressure to electrotactile feedback, thereby enhancing the user's perception.

[0098] While embodiments of the present disclosure have been described in detail above, those skilled in the art can make various modifications and variations to the embodiments of the present disclosure without departing from the spirit and scope thereof. It should be understood that, to those skilled in the art, these modifications and variations will still fall within the spirit and scope of the embodiments of the present disclosure as defined in the claims.

Claims

1. A flexible tactile sensing system, characterized in that, include: Electronic skin (10), the electronic skin (10) includes a piezoresistive functional layer (110) and an electrode layer (120), the piezoresistive functional layer (110) contacts the object to be grasped and detects the pressure of the object being grasped, and the electrode layer (120) contacts the skin of the hand; The driving device (20) includes a control module (210) and a current source module (220). The control module (210) is electrically connected to the piezoresistive functional layer (110) and the current source module (220). The control module (210) receives the pressure signal from the piezoresistive functional layer (110) and controls the current source module (220) to output current to the electrode layer (120). The electronic skin (10) further includes an insulating base layer (130) made of insulating material, the piezoresistive functional layer (110) includes a plurality of spaced pressure detection pieces, and the electrode layer (120) includes a plurality of spaced electrode patches. The pressure detection pieces and the electrode patches are arranged in pairs and are distributed one-to-one on two opposing sides of the insulating base layer (130).

2. The flexible tactile sensing system according to claim 1, characterized in that, The insulating substrate layer (130) includes a first surface and a second surface that are opposite to each other, and the electronic skin (10) further includes: Two electrode conductive layers (140) are provided, one of which is disposed on the first surface and electrically connected to the piezoresistive functional layer (110) and the driving device (20), and the other electrode conductive layer (140) is disposed on the second surface and electrically connected to the electrode layer (120) and the driving device (20).

3. The flexible tactile sensing system according to claim 2, characterized in that, The electronic skin (10) also includes: Two encapsulation protective layers (150) are made of insulating material. The two encapsulation protective layers (150) are respectively disposed on the side of the two electrode conductive layers (140) away from the insulating base layer (130). One of the encapsulation protective layers (150) has a first cutout (151) at a position corresponding to the pressure detection piece to expose the pressure detection piece. The other encapsulation protective layer (150) has a second cutout (152) at a position corresponding to the electrode patch to expose the electrode patch.

4. The flexible tactile sensing system according to any one of claims 1 to 3, characterized in that, The piezoresistive functional layer (110) includes at least one of carbon black, graphene, carbon nanotubes, graphite, carbon nanofibers, metal micro / nano powders / wires / sheets, MXene, liquid metal, PEDOT:PSS, polypyrrole, and polyaniline.

5. The flexible tactile sensing system according to claim 2, characterized in that, The electrode conductive layer (140) and electrode layer (120) are made of conductive materials, including at least one of silver paste, gold, copper, aluminum, carbon-based materials, metal nanowires, liquid metal, conductive polymers, and conductive hydrogels.

6. The flexible tactile sensing system according to claim 3, characterized in that, The piezoresistive functional layer (110), the encapsulation protective layer (150), the electrode conductive layer (140), the insulating substrate layer (130), and the electrode layer (120) are all made of flexible materials.

7. The flexible tactile sensing system according to any one of claims 1 to 3, characterized in that, The drive unit (20) further includes: A power supply module (240) is electrically connected to the current source module (220) and the control module (210); The communication module (250) is used to communicate with the host computer.

8. The flexible tactile sensing system according to any one of claims 1 to 3, characterized in that, The flexible tactile sensing system also includes: A flexible ribbon cable assembly (30) connects the driving device (20) and the electronic skin (10). The flexible ribbon cable assembly (30) includes a sensing flexible ribbon cable (310) and an electrode flexible ribbon cable (320). The sensing flexible ribbon cable (310) is electrically connected to the piezoresistive functional layer (110), and the electrode flexible ribbon cable (320) is electrically connected to the electrode layer (120).

9. The flexible tactile sensing system according to any one of claims 1 to 3, characterized in that, The driving device (20) is provided with a grounding node, and the flexible tactile sensing system further includes: The public ground patch module (40) is connected to the grounding node of the drive device (20). The public ground patch module (40) is used to contact the user's skin to form a circuit with the electrode layer (120) to achieve electrical stimulation.

10. A wearable device, characterized in that, include: The flexible tactile sensing system as described in any one of claims 1 to 9.

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