Flexible electric tactile device with adjustable fitting structure and modular electrode array

Abstract

The invention discloses a flexible electric tactile device with an adjustable fitting structure and a modular electrode array. The flexible electric tactile device comprises a driving circuit control structure and a glove which are fixed on a wrist; the flexible electrode assembly is in signal connection with the driving circuit control structure; the fingertip inertial sensor assembly is in signal connection with the driving circuit control structure; wherein the flexible electrode assembly comprises a plurality of fingertip electrode array modules and a plurality of palm electrode array modules, each fingertip electrode array module and each palm electrode array module are respectively in signal connection with the driving circuit control structure, and each fingertip electrode array module is adjustably fixed on a finger. The fingertip inertial sensor assembly comprises a plurality of fingertip inertial sensor units and a driver in signal connection with the plurality of fingertip inertial sensor units. According to the invention, through collaborative optimization of a flexible structure, electrode partition and signal control, tactile perception in a virtual environment is finer, more real and more controllable.

Description

Technical Field

[0001] This invention relates to the technical field of tactile gloves, and in particular to a flexible electrotactile device having an adjustable fit structure and a modular electrode array. Background Technology

[0002] With the rapid development of virtual reality (VR), augmented reality (AR), and remote operation, haptic feedback, as a key element in achieving immersive experiences and high-precision interaction, is receiving increasing attention. However, existing wearable haptic devices still mainly rely on mechanical or pneumatic solutions, making it difficult to achieve a balance between high resolution, lightweight design, and cost control.

[0003] Currently, the mainstream haptic feedback solutions mainly include the following categories: 1. Microfluidic Actuation Solution: The microfluidic actuation solution, represented by HaptX products, has now been commercialized. Its representative model is the HaptX Gloves DK2. 1 With HaptX Gloves G1 2 Both devices boast high spatial resolution, with electrode arrays of 133 and 135 points respectively. However, the devices still face the dual bottlenecks of bulkiness and high cost: the DK2 weighs over 30 kg and costs approximately $75,000; while the G1 has reduced its weight to 17 kg, it still requires a one-time purchase fee of $6,000 plus a monthly subscription fee of $500.

[0004] 2. Pneumatic Actuation Solutions: There is relatively little product and research on pneumatic actuation solutions, with the Meta Haptic Glove being a prime example. Its complex control system adjusts the inflation level to generate pressure at different points on the hand. The Meta team has made breakthroughs in pneumatic actuators that use air pressure to generate force and in electric actuators that change shape or size in the presence of an electric field. To control these new soft actuators, they are building a high-speed microfluidic processor—a microfluidic chip on the glove—that controls the airflow to the moving actuator by telling the valve when and how far it closes. Unlike the broader field of microfluidics, they emphasize making things extremely lightweight, wearable, and fast, achieving millisecond-level response times with air.

[0005] 3. Vibration feedback scheme: This is currently the most popular tactile method, but it has long been limited by the bottleneck of low resolution.

[0006] The bHaptics TactGlove DK1 glove features six haptic feedback points, each equipped with an LRA motor, with five located at the fingertips and one at the wrist. This allows for a realistic experience of grasping, touching, and pressing objects in virtual reality. Furthermore, made from lightweight, elastic materials, the glove is comfortable to wear and easy to put on and take off.

[0007] TactGloves integrates easily into popular software such as Unreal Engine and Unity, and connects via Bluetooth Low Energy (BLE) technology. Battery life is 3.5 hours, and it can be fully charged in 2 hours using a 5V 0.5A (maximum) charger.

[0008] This vibration is similar to other haptic feedback gloves, but they all have limitations in the precision of stimulation and cannot render fine textures and complex effects.

[0009] 4. Force Feedback Solution: Haptic devices have a relatively fixed rendering range and cannot render material textures, contact surface features, etc. Force feedback for the entire hand is exemplified by the Senseglove Nova2. This glove combines force and vibration feedback. Active haptic bands apply different pressures to the user's palm, while magnetic friction actuators apply resistance. Senseglove simulates the feel of size and stiffness. Nova integrates four dedicated brakes for each finger from thumb to ring finger. Each brake provides up to 20N of force. Senseglove incorporates advanced voice coil actuator technology; the thumb and index finger each have their own vibratory haptic actuator, while the voice coil actuator is located at the center of the glove.

[0010] Or it could be fingertip force feedback, like with ContactGlove. ContactGlove's haptic functionality uses "microcoils," which are coils wound very tightly. Their shape memory alloy causes the finger element to suddenly contract or expand again. Ideally, this creates a pressure sensation on the finger, similar to the touch of a real object. This technology can even simulate the shooting buttons, triggers, and stick inputs of classic controllers.

[0011] Many force-feedback wearable haptic devices are used as references in the research, but most are bulky and only serve specific rendering effects. A similar device is the one in UIST '21, which uses fingertip pressure to change the perceived stiffness of a contact object. Another example is "Fingertip Tactile Devices for Virtual Object Manipulation and Exploration," which uses a pair of fingers to deform the skin on the fingertips to transmit skin force information about object manipulation. Users can perceive differences in the weight of virtual objects, and as the rendering quality increases, they apply more and more gripping force when lifting virtual objects. Current mainstream haptic feedback solutions struggle to balance high spatial resolution, low cost, and lightweight design, limiting their widespread application in wearable devices and human-computer interaction.

[0012] In contrast, electrotactile feedback technology generates diverse and realistic tactile sensations by directly stimulating nerve endings on the skin surface with a weak electric current, without relying on mechanical deformation or physical contact.

[0013] This technology can simulate the texture, shape, and various force characteristics of different materials by precisely controlling the frequency, amplitude, and waveform of the current, and has high controllability and good expansion potential.

[0014] Therefore, electrotactile feedback is considered an important development direction for next-generation high-fidelity haptic feedback technology. However, related systems are still in the laboratory research stage, and lightweight, commercially viable mature products with varying stiffness have not yet been developed.

[0015] 1. Full hand skin patch While WeTac and FIBHT have taken an exploratory step in the field of flexible wearable haptic technology, both remain at the "laboratory-grade" skin patch paradigm: relying on adhesive layers to adhere to the palm. They lack adjustable size / tension structures and cannot adapt to different hand shapes and skin types; the bonding method is limited to "sticking," and they are still significantly far from being truly "product-grade haptic gloves."

[0016] A. WeTac system: The WeTac system employs ultra-thin, flexible skin electronics technology, consisting of a miniature flexible control unit and a high-density palm electrode array patch. It boasts a spatial resolution of approximately 1.8 pixels per square inch and an average center-to-center electrode spacing of 13 millimeters, achieving full-area coverage from the fingertips to the entire palm. The system adheres stably to the palm skin surface, adapting to natural deformations such as stretching and bending. Because different areas of the hand exhibit significantly different sensitivity thresholds to electrical stimulation, WeTac supports rapid, individualized threshold calibration for each user's palm. It can adaptively adjust the stimulation intensity based on the sensitivity differences in different areas, enhancing the system's safety, comfort, and user versatility.

[0017] B. FIBHT system: FIBHT (Fabric-Integrated Breathable Haptic Textile) is a fully integrated breathable tactile textile system optimized to address the problems of poor breathability, insufficient biocompatibility, and discomfort during prolonged wear in existing wearable tactile devices. The system integrates 128 high-density electrostimulation electrode units in the palm, combining an electrospun SBS elastic fiber substrate, liquid metal conductive pathways, and a hydrogel interface layer to create a thin, soft, and skin-conforming structure with excellent breathability, stretchability, and stability, allowing for continuous operation in both dry and humid environments. Through multiplexing control and a wireless drive module, FIBHT achieves crosstalk-free, high-resolution, multi-mode dynamic tactile feedback, effectively improving the environmental adaptability and long-term wearing comfort of wearable systems.

[0018] 2. Partially fixed / finger-tip wearing form as the core Robotics X Lab, in collaboration with City University of Hong Kong, has developed a haptic feedback glove based on low-voltage electrotactile stimulation. The core hardware design of the Super-resolution wearable electrotactile rendering system is as follows: each fingertip is equipped with a 5×5 electrode array, totaling 25 microelectrodes; the entire array is printed on a thin, flexible printed circuit board (FPC) and worn inside a rubber finger sleeve. The electrode surface features a hemispherical metal protrusion structure, greatly increasing the contact area with the skin and improving conductivity stability, thus delivering a highly sensitive, high spatial resolution haptic feedback experience.

[0019] PS: Other research on electrotactile gloves mostly focuses on the fingertips, fixing dry electrodes to the fingertips using FPC or PCB (or electronic skin). However, it does not address issues related to fit and long-term use. Here are some additional recent electrotactile research, not in glove form, such as electrode distribution providing weight sensing, stiffness sensing, and the perception of objects in front.

[0020] Limitations of existing technologies: Electrode fit in electrotactile gloves is insufficient. Wearable hand-based tactile devices demand high levels of softness, fit, and thinness. However, existing devices generally suffer from bulky or overly rigid fingertip structures. While electrotactile technology has a natural advantage in terms of lightweight design compared to other tactile feedback methods, the degree of electrode fit significantly impacts the tactile experience. Due to significant individual hand size variations, especially in the fingertip area, existing structures lack effective adjustment mechanisms, making personalized adaptation difficult.

[0021] Furthermore, the flexibility of existing electrode arrays primarily relies on the overall bending of the substrate material (such as PI), leading to internal stress concentration and a lack of independent elastic deformation capability at the individual electrode unit level. In areas with greater curvature, such as the hand, localized suspension, pressure, or uneven contact can easily occur, resulting in unstable electrode-skin contact, affecting stimulation consistency and comfort, and making it difficult to achieve precise adaptation and close fit to the hand shape. While some "electronic skin" solutions that adhere to the skin possess flexibility, they currently lack the potential for low-cost, mass production and compatibility with all users (due to non-adjustable size).

[0022] Lack of wearability and replaceability: Most current electrotactile gloves fix the electrode array to the glove fabric body, failing to consider the maintenance and replacement needs during long-term use. In practical applications, sweat easily accelerates the oxidation of the electrode surface, leading to changes in contact impedance and significantly reducing the stability of the electrical stimulation experience. However, existing structures generally lack modular design, making it difficult to replace damaged electrodes individually, resulting in the scrapping of the entire device, increasing usage costs, and limiting product sustainability and user acceptance.

[0023] 3. Lack of motion capture adaptability Gesture recognition plays a crucial role in future virtual environment experiences. However, the structure of the glove itself often interferes with the optical gesture recognition system built into head-mounted displays, leading to decreased hand motion capture accuracy and issues such as recognition delays, posture drift, or false triggers, severely impacting the naturalness and accuracy of human-computer interaction. Most lightweight haptic gloves do not integrate gesture recognition functionality or only provide a mechanical interface to external positioners (such as the HTC VIVE Tracker), lacking deep adaptation to mainstream motion capture systems.

[0024] 4. Summary The existing electro-haptic glove structure is still immature. Apart from adhesive electronic skin developed in laboratories (which is difficult to commercialize), other electro-haptic devices generally suffer from poor fit, non-replaceable electrodes, and interference with motion capture. This invention achieves an adjustable-size, highly fitted glove structure with replaceable electrodes through structural design, and includes a reserved IMU fingertip fixing interface, thus solving the problems of comfort, fit accuracy, and compatibility in one go, significantly improving the overall product performance. Summary of the Invention

[0025] To address the shortcomings of existing technologies, the present invention aims to provide a flexible electrotactile device with an adjustable fit structure and a modular electrode array, thereby solving the problems of large size, heavy weight, slow response, and poor fit in existing mechanical tactile gloves. To achieve the above-mentioned objectives and other advantages of the present invention, a flexible electrotactile device with an adjustable fit structure and a modular electrode array is provided, comprising: A drive circuit control structure and glove fixed to the wrist; Flexible electrode assembly connected to the drive circuit control structure signal; The fingertip inertial sensor assembly is connected to the control structure of the drive circuit via signal transmission. The flexible electrode assembly includes multiple fingertip electrode matrix modules and multiple palm electrode matrix modules. Each fingertip electrode matrix module and each palm electrode matrix module are respectively connected to the drive circuit control structure signal. Each fingertip electrode matrix module can be adjusted and fixed on the finger. The fingertip inertial sensor assembly includes multiple fingertip inertial sensor units and a driver that is signal-connected to the multiple fingertip inertial sensor units. The driver is signal-connected to the drive circuit control structure. Each fingertip inertial sensor unit corresponds to a fingertip electrode matrix module, and each fingertip inertial sensor unit is plugged into the fingertip electrode matrix module.

[0026] Preferably, the glove uses a flexible printed circuit board (FPC) as its core carrier, with a high-density electrode array deployed in the palm and finger areas, combined with a self-locking adjustable fit structure to achieve lightweight and high-resolution electrotactile feedback. The electrode module adopts a modular and detachable design for easy maintenance and replacement; the flexible serpentine wires maintain stable conductivity even after repeated bending. The control module is integrated into the wrist, containing a high-voltage drive circuit, a signal modulation unit, and a wireless communication module, supporting multi-channel electrical stimulation output and millisecond-level real-time feedback. The entire glove weighs approximately 100 grams, and the FPC (electrode) thickness is approximately 0.16 mm, exhibiting excellent flexibility and wearing comfort.

[0027] Preferably, the fingertip electrode matrix module includes a flexible circuit board strip and wires fixed on the flexible circuit board strip. The flexible circuit board strip has a T-shaped structure, wherein the flexible circuit board strip includes a fixed end, a plug-in end integrally connected to the fixed end, and a wire fixing end.

[0028] Preferably, the fixed end has multiple fixed slots, and the end of the insertion end away from the fixed end is a positioning flange that matches the fixed slots; and the insertion end has a snap-fit ​​piece that matches the slots.

[0029] Preferably, each of the fingertip inertial sensor units is fixed to a driver, which is fixed to the glove.

[0030] Preferably, the glove includes a wearable glove and a back-of-hand fixing sleeve fixed to the wearable glove. The back-of-hand fixing sleeve is fixed to the wrist, the fingertip inertial sensor assembly passes through the back-of-hand fixing sleeve, and the flexible electrode assembly passes through the wearable glove and is connected to the drive circuit control structure.

[0031] This invention proposes a flexible electro-tactile glove with an adjustable fit structure and a high-density modular electrode array through systematic optimization of structure, materials, and electrical control. The device achieves a comprehensive balance between lightweight, flexibility, and tactile resolution, offering excellent wearability and engineering feasibility.

[0032] The present invention has the following beneficial effects: I. Significantly Improved Fit and Comfort: Most existing electrotactile devices use planar PI films or gel patches as electrode interfaces. The former is difficult to achieve a perfect fit with changes in fingertip curvature, while the latter, although soft, has a cold and sticky surface, easily causing skin discomfort and irritation after prolonged wear. Furthermore, gel dries out easily and cannot be reused. This invention employs a flexible printed circuit board (FPC) combined with a serpentine conductor and elastic electrode island design, giving each electrode unit independent elastic deformation capabilities. Simultaneously, a self-locking adjustable fit structure allows the electrode array to automatically adapt to different hand shapes and local curvatures. This structure significantly improves the stability of electrode-skin fit, reduces contact impedance fluctuations, and avoids the discomfort associated with traditional adhesive structures, resulting in a more natural, smooth, and stable overall wearing experience.

[0033] II. Modular Structure Design for Easy Maintenance and Replacement: Traditional electro-tactile gloves often employ an integrated electrode and fabric structure. Once the electrodes age or are damaged, the entire device needs to be replaced, resulting in high maintenance costs and unsustainability. This invention proposes a modular electrode array solution. Each electrode module is independently connected to the drive circuit board via a standardized interface, allowing for individual installation, removal, replacement, or upgrades. The glove body and electrode layer adopt a composite structure of "circuit separation + snap-fit ​​fixation," enabling the fabric to be washed and the electrodes to be reused, significantly improving the maintainability, sustainability, and lifespan of the equipment.

[0034] III. Motion Capture Compatibility and Real-Time Closed-Loop Feedback Existing gloves generally suffer from problems such as large thickness, strong reflectivity, or complex external structures, which can easily interfere with the recognition of optical motion capture systems. This invention fully embeds the flexible circuitry and fabric layer into a single integrated unit, with an overall thickness of only about 0.16 mm. The surface has no reflective elements or protruding structures, ensuring seamless compatibility with mainstream optical tracking devices. The system reserves an inertial measurement unit (IMU) interface on the FPC, utilizing the adjustment slot reserved in the FPC through electrical stimulation to achieve a stable embedding of the IMU and the finger sleeve. This design ensures closed-loop feedback of motion and touch during virtual interaction, enhancing immersion and operational accuracy.

[0035] IV. Lightweight and Slim Design for Superior Wearing Experience: Traditional mechanical or pneumatic haptic gloves are often bulky and heavy, causing hand fatigue with prolonged wear, making them unsuitable for everyday interactive scenarios. This invention weighs approximately 100 grams, with flexible electrodes approximately 0.16 millimeters thick, and a compact and rationally arranged drive module. Through a zoned fabric design (low-elasticity bird's-eye fabric, fine mesh fabric, Roman cloth, and polyester-cotton blends, etc.), it achieves high breathability and a comfortable fit while ensuring conductivity stability. The overall structure is lightweight and soft, suitable for extended wear, without affecting natural grip, bending, and fine motor skills, significantly improving the user experience in virtual reality and remote interaction.

[0036] V. Low Cost and Scalable Manufacturing Advantages Existing high-resolution tactile devices mostly employ microfluidic actuation or high-precision mechanical structures, resulting in high costs, complex manufacturing processes, and difficulties in mass production. For example, the unit cost of HaptX and Meta solutions typically ranges from tens of thousands to hundreds of thousands of RMB. This invention utilizes standard FPC technology, fabric stitching technology, and magnetic module assembly, with a mature manufacturing process and readily available materials, enabling mass production within the existing electronics processing industry chain. The material and manufacturing cost of a single glove can be controlled to within 1,000 RMB, significantly lower than similar products. The modular interface design further reduces assembly steps and maintenance costs, giving the system extremely high production scalability and commercial potential.

[0037] In summary, this invention, through a comprehensive design of "adjustable fit structure + flexible modular electrode array + thin fabric layer + integrated control system," successfully solves the problems of insufficient fit, uncomfortable gel patches, bulky structure, and high cost of existing electro-haptic gloves. It achieves a balance of lightweight, low cost, high comfort, and high-resolution haptic feedback, significantly improving the overall performance of the device in terms of stability, economy, and scalability. This provides a new technical path for the practical application and mass production of flexible wearable haptic interaction devices. Attached Figure Description

[0038] Figure 1This is a three-dimensional structural diagram of a flexible electrotactile device with an adjustable fit structure and a modular electrode array according to the present invention. Figure 2 A diagram showing the fabric composition of a glove for a flexible electrotactile device with an adjustable fit structure and a modular electrode array according to the present invention. Figure 3 A key diagram showing the wearing process of each part of the flexible electrotactile device with an adjustable fit structure and a modular electrode array according to the present invention. Figure 4 A diagram illustrating the self-locking method of the fingertip FPC of the flexible electrotactile device with an adjustable fitting structure and modular electrode array according to the present invention. Figure 5 This is a schematic diagram of the attachment method of the fingertip IMU of the flexible electrotactile device with adjustable fitting structure and modular electrode array according to the present invention. Figure 6 This is a schematic diagram showing the distribution of hand tactile sensitivity and the division of electrode arrangement areas in the flexible electrotactile device with an adjustable fitting structure and modular electrode array according to the present invention. Figure 7 A schematic diagram showing the hand electrode array arrangement and parameter annotations of a flexible electrotactile device with an adjustable fit structure and modular electrode array according to the present invention. Figure 8 A schematic diagram showing the hand electrode array arrangement and parameter annotations of a flexible electrotactile device with an adjustable fit structure and modular electrode array according to the present invention. Figure 9 This is a schematic diagram illustrating the manufacturing process and dimensional design of the flexible electrode structure of the flexible electrotactile device with an adjustable fitting structure and a modular electrode array according to the present invention. Figure 10 This is a schematic diagram comparing the structural principle and deformation characteristics of the elastic electrode unit of the flexible electrotactile device with adjustable fit structure and modular electrode array according to the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Reference Figure 1 A flexible electrotactile device with an adjustable fit structure and a modular electrode array, comprising: The drive circuit control structure, fixed to the wrist, comprises a main control chip, an electrical stimulation drive circuit, a power management circuit, a signal modulation unit, and a communication interface module. The drive circuit module is encapsulated within the drive housing 1 and connected to the other structures of the glove. The main control chip receives external interactive commands, distributes multi-channel signals, and adjusts stimulation parameters in real time. The electrical stimulation drive circuit converts the control signal into an adjustable current output, ranging from 0.1 to 5 mA in frequency from 1 to 1000 Hz. It can generate square waves, pulse waves, or sine waves according to different stimulation modes, thereby producing corresponding tactile sensations on the skin surface. The drive circuit control module 2 is integrated onto a flexible printed circuit board (FPC) of approximately 25 square centimeters. This highly integrated design of the drive circuit control structure provides the foundation for the wearability of the system and is fixed to the wrist via an adjustable strap 4. It is the core control and signal output unit of the entire electrotactile system.

[0041] In one embodiment, the power management circuit includes a boost converter and a voltage regulator module, which can boost the voltage of a 3.7V, 1200mAh lithium battery to the target high voltage, ensuring stable power supply even when multiple electrodes are driven in parallel. The communication interface module adopts Bluetooth Low Energy (BLE) connectivity to achieve bidirectional communication with the host device and supports firmware updates and energy management.

[0042] In one embodiment, the drive circuit control structure is connected to multiple fingertip electrode matrix modules 7 and multiple palm electrode matrix modules 8 to form a multi-channel independent control path. The output waveform and intensity of each electrode module can be individually adjusted by the main control chip to achieve zoned tactile feedback.

[0043] In one embodiment, the drive circuit control structure and the hand IMU accessory 5 are connected via a high-speed serial port, sharing power and data buses to achieve millisecond-level synchronization of gesture movements and tactile stimuli. Five extended IMU chips are fixed to the fingertip, and the entire FPC is sandwiched in the middle of the fixing fabric layer 4 to ensure stable wearing.

[0044] Through the above design, the present invention achieves integrated driving, power supply, communication and sensing functions, while significantly reducing size and weight, and ensuring system response speed, output stability and scalability.

[0045] like Figure 2As shown, this invention employs a zoned fabric design in the glove structure to meet the differentiated needs of different areas in terms of flexibility, electrical performance, and ergonomics. All flexible circuitry is integrated with the fabric through a sewing process, achieving structural separation between the entire circuit system and the glove body. This facilitates modular replacement and functional upgrades, and allows for fabric replacement and maintenance without disassembling the circuitry. The glove includes a wearable glove and a back-of-hand fixing sleeve fixed to the wearable glove. The back-of-hand fixing sleeve is fixed to the wrist, and the fingertip inertial sensor assembly passes through the back-of-hand fixing sleeve. The flexible electrode assembly passes through the wearable glove and connects to the drive circuit control structure. The finger side areas of the wearable glove use low-elasticity bird's-eye fabric 9, a material woven from nylon and spandex composites, which has high elasticity and excellent breathability, adapting to the frequent bending movements of the fingers. The palm area uses fine mesh fabric 10, a lightweight, soft, and delicate material that reduces local pressure while maintaining the stability of the conductive layer, improving comfort during extended wear. The main hand area uses Roma fabric 11 with an internal wiring loop structure to secure the fingertip wires and prevent tangling or displacement during complex movements. This layer also provides stable support and torsional resistance, ensuring neat and reliable signal circuitry while maintaining flexibility and bendability.

[0046] The inner IMU's back-of-hand fixing sleeve uses polyester-cotton fabric 12 as the fixing base. Its three-dimensional support fiber structure can effectively distribute the force on the wrist and prevent local pressure. The drive module is doubly fixed to this area by a wristband and magnetic buckle, and the tightness can be adjusted by the wristband adjustment structure to ensure the stability and safety of the module during wearing.

[0047] This invention combines ergonomics and maintainability through a structural design of "fabric partitioning + circuit separation + full stitching connection". The gloves are lightweight, breathable, washable, and replaceable. The circuit modules are independently detachable, facilitating future maintenance and modular upgrades, thus achieving comfort, reliability, and sustainable use during long-term wear.

[0048] One embodiment, such as Figure 3 As shown in Figures a to k, the flexible electro-tactile glove of this invention adopts a modular assembly structure, which facilitates users to quickly complete the installation of the drive module, electrode connection, and overall device donning. Through a structure-oriented assembly principle, stability and safety are fully guaranteed after wearing.

[0049] (a) The back of the hand is wrapped around the wrist and closed with Velcro to form a ring structure, providing a support base for the drive module.

[0050] (b) The wrist strap is fitted onto the outside of the drive support layer and fixed to the drive housing, and the tightness of the buckle is adjustable.

[0051] (c) A female opening is provided on the back of the hand fixing sleeve, and a female buckle is installed inside the drive. The inside and outside attract each other to complete the further fixation of the outer shell and the fabric layer and prevent slippage.

[0052] (d) Place the battery assembly into the slot at the bottom of the drive housing, with a margin between the battery and the chip area to prevent interference and improve heat dissipation.

[0053] (e) Slide the main control chip into the drive module slot along the guide groove, position and fix it.

[0054] (f) Lead out the signal receiving antenna and insert it into the external antenna slot to maintain stable communication.

[0055] (g) The gloves have zippers on the side for easy putting on and taking off, and also make it easy to place the palm electrode pads in the correct position.

[0056] (h) Insert the flexible FPC of the finger electrode into the drive module connection port, and fix the back of the hand with a small hole for the FPC to pass through.

[0057] (i) The electrical stimulation FPC of the middle and ring fingers is inserted into the annular guide groove inside the glove to avoid entanglement and fix the direction.

[0058] (j) The FPC stimulation electrode and IMU sensor are fixed in the finger area to keep it stable during bending and grasping movements. The IMU FPC is outside the fabric layer, and the electrical stimulation FPC is pressed inside the fabric layer, closely attached to the skin to fix the finger area.

[0059] (k) Finally, insert the hardware structure of the distinguishing circuit into the drive support layer guide groove in the direction of the arrow to prevent the IMU from slipping out of the interlayer and complete the overall assembly.

[0060] Through the above steps, this invention achieves rapid assembly and self-positioning of the drive, power supply, electrodes, and sensing modules, all without the need for specialized tools. The modular interface design provides the system with excellent maintainability and expandability, while ensuring structural stability, signal reliability, and long-term wearing comfort.

[0061] One embodiment, such as Figure 4As shown, the flexible electrode assembly includes multiple fingertip electrode matrix modules and multiple palm electrode matrix modules. Each fingertip electrode matrix module and each palm electrode matrix module are respectively connected to the drive circuit control structure. Each fingertip electrode matrix module can be adjusted and fixed on the finger. The fingertip electrode matrix module includes a flexible circuit board strip and wires fixing the flexible circuit board strip. The flexible circuit board strip has a T-shaped structure, including a fixed end, a plug-in end integrally connected to the fixed end, and a wire fixing end. The fixed end has multiple fixed slots, and the end of the plug-in end away from the fixed end is a positioning flange that matches the fixed slots; and the plug-in end has a snap-fit ​​piece that matches the slot. As shown in Figures ① to ⑤, the present invention uses a flexible circuit board (FPC) in the fingertip area and designs the FPC into an adjustable tightness wearable fixing structure to achieve quick assembly and stable fit. This structure allows the electrode module to be adaptively fixed for different finger sizes, ensuring that the electrodes maintain stable contact and signal continuity even during dynamic bending and high-frequency movement.

[0062] First, the flexible printed circuit board (FPC) is wrapped around the designated area of ​​the finger or hand, and the appropriate position is selected according to the wearer's hand size (steps ① and ②). The electrode area and the wire arrangement layer on the FPC are kept flexible and continuous, so that it can naturally conform to the curvature of the finger after being folded.

[0063] Subsequently, a quick-locking mechanism (steps ③ to ④) is used to complete the fastening process. This mechanism consists of two sets of complementary slots. The user simply needs to press lightly to insert the connector; the positioning flange at the insertion end inserts into the slot, and the snap-fit ​​tab then inserts into another slot to secure it, requiring no additional tools or adhesives. After the latches close, the FPC electrode is fixed at the fingertip position. The extended circuitry is ultimately encased in a fabric layer.

[0064] Finally (step ⑤), a complete closed-loop structure is formed in the fingertip area, and the FPC electrode maintains stable contact with the skin surface, so that the wearer does not have a noticeable foreign body sensation when making fists, bending or tapping.

[0065] Through the above structural design, this invention achieves rapid installation, secure fit, and adjustable tightness of the fingertip area electrode module. This solution not only improves wearability and reusability but also avoids the problems of easy detachment and difficult maintenance associated with traditional adhesive or strap fixing methods, providing a reliable solution for the modular assembly of high-density electrotactile systems.

[0066] One embodiment, such as Figure 1 , 5As shown, the fingertip inertial sensor assembly includes multiple fingertip inertial sensor units and a driver that is signal-connected to the multiple fingertip inertial sensor units. The driver is signal-connected to the drive circuit control structure. Each fingertip inertial sensor unit corresponds to one fingertip electrode matrix module, and each fingertip inertial sensor unit is plugged into the fingertip electrode matrix module. As shown in Figures ① and ②, the IMU inertial sensor module of the present invention adopts an integrated design with a flexible printed circuit board (FPC), and achieves precise positioning and stable connection of the module in the finger sleeve area through a T-shaped interface structure. The two ends of the fingertip inertial sensor unit are respectively inserted into slots.

[0067] The IMU module and FPC circuitry are integrated on the same flexible substrate. The module dimensions are approximately 24.0 mm × 8.0 mm, and the interface width is 4.0 mm. During installation, insert the FPC connector with the integrated IMU into the adjustment slot on the side wall of the finger sleeve in the direction of the arrow (step ①) to achieve positioning and stability. After insertion (step ②), the module and the outer layer of the finger sleeve will fit tightly together.

[0068] The structure is secured by the pressure applied when the FPC is electrically stimulated, eliminating the need for additional adhesives or threaded structures and ensuring high repeatability of assembly and disassembly. Through this design, the present invention achieves precise positioning and fixation of the IMU sensor within a limited space.

[0069] One embodiment, such as Figure 6 As shown, the hand area division and design basis are as follows: like Figure 1 As shown, this invention divides the hand into functional zones based on the two-point resolution threshold and tactile sensitivity distribution characteristics of different regions of the human hand, in order to determine the target area and density distribution strategy for electrode placement.

[0070] The tactile sensitivity of the human hand varies significantly across different areas: the two-point resolution threshold of the fingertips and fingertips is approximately 1–3 mm, classifying them as highly sensitive areas; the resolution threshold of the palm and the base of the fingers is approximately 6–12 mm; while the threshold of the back of the hand and the area below the palm base is greater than 20 mm, classifying them as low-sensitivity areas. Based on this physiological distribution pattern, this invention divides the hand into eight electrode placement areas, including the fingertips area for high-precision tactile stimulation and a large area of ​​palm muscle suitable for electrode attachment and signal diffusion.

[0071] The specific divisions are as follows: • Areas 1-5: Corresponding to the pads and tips of the thumb and four fingers, these are highly sensitive tactile areas suitable for deploying high-density microelectrode arrays; • Areas 6-8: Corresponding to the palm and the area near the base of the palm, these are medium-sensitivity areas, suitable for deploying medium-density electrodes for wide-area stimulation and tactile transition.

[0072] The results of this division form the basis for electrode arrangement design, providing a precise basis for the subsequent layout of electrode arrays of different sizes and densities, thereby realizing the spatial refinement and physiological adaptation design of electrotactile stimulation.

[0073] One embodiment, such as Figure 7 As shown, the electrode array arrangement scheme of the fingertip electrode array module and multiple palm electrode array modules is as follows: The actual circuit was fabricated, and the electrode areas of the fingers and palms were divided into zones and the number of electrodes was distributed.

[0074] Based on the operational precision and nerve density distribution, the finger area adopts a high-density dot matrix layout: Each of the three middle fingers (index, middle, and ring fingers) is equipped with 24 electrodes to provide fine tactile feedback. Sixteen electrodes are positioned in the little finger area for peripheral movement or auxiliary stimulation; The thumb area is equipped with 32 electrodes for tactile output of independent gripping and counter-grip movements.

[0075] The palm area is further divided into three functional sub-regions (a, b, and c), corresponding to different muscle and nerve pathways, with 16, 24, and 24 electrodes respectively, for a total of 64 electrode points. This zonal layout allows for continuous electrical stimulation over a large area of ​​the palm's muscles, simulating complex tactile sensations such as pressure, sliding, and wide-area contact.

[0076] Regarding electrode geometry parameters: The finger area employs a microelectrode layout with a diameter of 1 mm and a spacing of 1.5 mm to improve the spatial resolution of local stimulation; The palm area features a medium-density electrode layout with a diameter of 3 mm and a spacing of 3 mm to enhance coverage and comfort. Each electrode is connected by a flexible wire with a diameter of 0.11 mm, and the FPC carrying the circuit and electrodes branches to each module along the back of the hand.

[0077] Each electrode matrix module is electrically connected to the driver circuit board via a modular interface, enabling independent channel control. The modular wiring method facilitates replacement and maintenance while effectively reducing wiring complexity. This layout design fully considers the tactile discrimination capabilities and mechanical deformation characteristics of different areas of the hand, achieving high-density, multi-area, and scalable electrotactile output distribution while ensuring stable signal transmission.

[0078] like Figure 8As shown, in order to clarify the structural dimensions and arrangement of electrode arrays in different areas of the hand, this invention designs a variety of modular array forms for the finger and palm areas to adapt to the curved structure and tactile needs of different operating parts.

[0079] (1) Finger electrode module: • The thumb module is finely tuned in a 6×9 dot matrix layout, with a coverage area of ​​11 mm × 18.5 mm, to provide a larger contact area and high stimulation intensity, adapting to thumb bending and rotation movements. • The three middle fingers module (index finger, middle finger, and ring finger) adopts a 5×8 dot matrix layout for fine adjustment, with a single module area of ​​approximately 8.5 mm × 16 mm, which is suitable for fine operation and high-frequency tactile feedback; The little finger module features a finely tuned 5×6 dot matrix layout, with an area of ​​approximately 8.5 mm × 11 mm. Its compact structure is designed to supplement edge tactile sensation and provide balanced stimulation during gripping.

[0080] (2) Palm electrode module: The palm area is divided into three functional versions based on the curvature of the palm and the differences in muscle distribution, labeled as a, b, and c respectively.

[0081] • Layout a: Horizontal double column, vertical 5 rows layout, electrode spacing is 3 mm, suitable for shallow arc area near the base of the finger; • Layout b: Matrix 4×5 arrangement, with moderate coverage, suitable for the thenar eminence muscle bulge area; • Layout c: 5 columns vertically and 5 rows horizontally, designed for the flatter areas of the palm side, to achieve more stable contact and conductivity.

[0082] like Figure 9-10 As shown, the fingertip electrode matrix module uses elastic electrode units, and its construction parameters are as follows: The flexible electrode module of the present invention is fabricated based on flexible printed circuit (FPC) technology, and achieves integrated molding of fine wires and self-locking structure through high-precision processing to meet the requirements of high-density wiring and stable bonding.

[0083] In terms of manufacturing process, firstly, a circuit pattern with electrode dot matrix is ​​designed on a flexible printed circuit board (FPC), and then the conductive pattern is precisely transferred to the surface of the flexible substrate using standard flexible circuit processing technology (such as dry film exposure and etching) to form a preliminary conductive structure between the electrodes and signal wires (see Figure 9, left). Subsequently, high-precision laser cutting technology is used to process structural units with flexible and self-locking functions in key areas such as the fingertips and palms, enabling the electrode modules to automatically fit and securely fix according to different hand shapes, thereby improving the adaptability of wearing and the reliability of the structure (see Figure 9, right).

[0084] As shown in Figure 10, the flexible electrode unit has an overall thickness of approximately 0.16 mm, exhibiting excellent bendability and deformation stability. Its geometric parameters are as follows: Electrode island dimensions: 1 mm × 1 mm; center-to-center spacing: 2 mm; Serpentine conductive connector: width 0.06 mm, spacing 0.4 mm; Array pitch: 2 mm; module width approximately 23 mm, length approximately 66 mm.

[0085] This design ensures conductive continuity while providing excellent flexibility and mechanical durability, maintaining stable signal transmission even under repeated bending and dynamic stretching. The serpentine conductor structure effectively releases localized strain, allowing the electrode array to remain flat and conforming to complex curved surfaces, preventing breakage and warping. The flexible electrode unit structure of this invention can adapt to various curvature variations in hand areas, and is particularly suitable for high-motion areas such as the fingertips, palm, and wrist transition, providing a reliable foundation for stable, comfortable, and high-resolution tactile feedback in electro-haptic gloves.

[0086] The number of devices and processing scale described herein are for simplification of the invention. Applications, modifications, and variations of this invention will be readily apparent to those skilled in the art. Although embodiments of the invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this invention, and further modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A flexible electrotactile device with an adjustable fit structure and a modular electrode array, characterized in that, include: A drive circuit control structure and glove fixed to the wrist; Flexible electrode assembly connected to the drive circuit control structure signal; The fingertip inertial sensor assembly is connected to the control structure of the drive circuit via signal transmission. The flexible electrode assembly includes multiple fingertip electrode matrix modules and multiple palm electrode matrix modules. Each fingertip electrode matrix module and each palm electrode matrix module are respectively connected to the drive circuit control structure signal. Each fingertip electrode matrix module can be adjusted and fixed on the finger. The fingertip inertial sensor assembly includes multiple fingertip inertial sensor units and a driver that is signal-connected to the multiple fingertip inertial sensor units. The driver is signal-connected to the drive circuit control structure. Each fingertip inertial sensor unit corresponds to a fingertip electrode matrix module, and each fingertip inertial sensor unit is plugged into the fingertip electrode matrix module.

2. The flexible electrotactile device with an adjustable fit structure and a modular electrode array as described in claim 1, characterized in that, The fingertip electrode matrix module includes a flexible circuit board strip and wires fixed on the flexible circuit board strip. The flexible circuit board strip has a T-shaped structure and includes a fixed end, a plug-in end integrally connected to the fixed end, and a wire fixing end.

3. The flexible electrotactile device with an adjustable fit structure and a modular electrode array as described in claim 2, characterized in that, The fixed end is provided with multiple fixed slots, and the end of the plug-in end away from the fixed end is a positioning flange, which matches the fixed slots; and the plug-in end is provided with a snap-fit ​​piece, which matches the slot.

4. The flexible electrotactile device with an adjustable fit structure and a modular electrode array as described in claim 3, characterized in that, Each of the fingertip inertial sensor units is mounted on a driver, which is mounted on the glove.

5. The flexible electrotactile device with an adjustable fit structure and a modular electrode array as described in claim 1, characterized in that, The glove includes a wearable glove and a back-of-hand fixing sleeve fixed to the wearable glove. The back-of-hand fixing sleeve is fixed to the wrist. The fingertip inertial sensor assembly passes through the back-of-hand fixing sleeve. The flexible electrode assembly passes through the wearable glove and is connected to the drive circuit control structure.

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