Intelligent insole for plantar pressure detection and preparation method thereof

Abstract

The invention discloses an intelligent insole for plantar pressure detection and a preparation method thereof. The intelligent insole comprises a plantar flexible sensor, an information acquisition module and a wireless communication module, the plantar flexible sensor comprises a flexible PCB electrode layer, a pressure-sensitive layer and a protective layer and is used for collecting plantar pressure signals and sending the plantar pressure signals to the information collection module. The pressure-sensitive layer comprises a plurality of micro-structure pressure-sensitive modules which are embedded into the sensing units of the electrode layer of the flexible PCB, and the plurality of micro-structure pressure-sensitive modules are connected through electrodes to form a flexible sensor array; the information acquisition module is used for receiving and processing a plantar pressure signal acquired by the plantar flexible sensor and converting an analog signal into a digital signal; and the wireless communication module is used for transmitting the processed digital signal to a terminal system. The foot information is accurately collected, and doctors are assisted in diagnosis and rehabilitation treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of plantar pressure detection, and in particular to an intelligent insole for plantar pressure detection and a preparation method thereof. Background Art

[0002] In recent years, with the advancement of science and technology, research techniques for plantar pressure testing have become more mature. From simple footprint detection methods to light sectioning methods, and then to visualization systems using sensors and force plates, data accuracy and application scope have gradually improved. The original footprint method involved rubbing the foot's footprint onto easily deformable or visible objects such as ink paper, molding sand, rubber, and plasticine. Because high-pressure areas leave noticeable marks, while low-pressure areas are relatively shallow, this method allows for qualitative analysis of the distribution of foot pressure. Later, to quantitatively analyze foot pressure, the optical light sectioning method emerged. Light sectioning is a method commonly used to measure surface roughness. When incident light is directed at a certain angle to the object being measured, the light band is affected by the surface, resulting in different images. In the measurement of plantar pressure, different pressures will cause the support platform to deform to varying degrees, thus affecting the refraction of light. By mapping different projected images with corresponding pressures, the difference in pressure in some areas can be quantified. Subsequently, some scholars used force-sensitive sensors to produce a new type of plantar pressure analyzer, a force plate and a force platform. They generated pressure by having the tester stand on the force plate / platform, causing the internal sensor to generate a corresponding pressure distribution signal.

[0003] With the maturity of force-sensitive sensor technology, force plates have become mainstream devices. Patent CN221383545U is a distinctive example. It discloses a plantar pressure detection and analysis device, comprising a data processing box, a first housing, a torque clip, a second housing, and a pressure sensor array. During use, the device must be fixed to the ground, locked in place by the torque clip to prevent tipping, and the user stands or walks on the sensor surface for measurement. However, similar static plantar pressure measurement devices have certain limitations. They require testing at a fixed location and cannot accurately measure pressure distribution under multiple motion conditions, which affects daily use. Measurement accuracy is subject to certain errors, and due to poor adhesion to the sole of the foot, accurate data is often difficult to obtain. Pressure shoes / insoles operate on similar principles to force plates, but utilize more flexible sensors to achieve dynamic, real-time measurement. They also collect more intensive data and can reflect the testee's true plantar pressure distribution. Patent CN118058554A proposes the following technical solution: three pressure monitoring zones are located within the insole body: the toes, sole, and heel. The insole incorporates a built-in pressure sensor module, battery module, signal processing module, and wireless communication module. However, current research mainly focuses on the design of plantar signal detection systems. Due to limitations in sensor size and process, it is difficult to array the sensors for accurate data collection. Therefore, when collecting and analyzing plantar signals, further data processing is required to eliminate interference data.

[0004] At present, most domestic devices only support static standing measurements, while real-time monitoring technology for dynamic movements such as running and jumping has not yet been popularized. In addition, due to the large size of the sensors, poor array effect, inaccurate sensor force, and poor attachment to the soles of the feet, the information obtained has certain errors. Summary of the Invention

[0005] The purpose of the present invention is to provide an intelligent insole for plantar pressure detection and a preparation method thereof, so as to accurately collect foot information and assist doctors in diagnosis and rehabilitation treatment.

[0006] To achieve the above object, the present invention provides the following solutions: An intelligent insole for detecting plantar pressure, comprising: a plantar flexible sensor, an information collection module, and a wireless communication module; The flexible plantar sensor includes a flexible PCB electrode layer, a pressure-sensitive layer, and a protective layer. It is used to collect plantar pressure signals and send them to an information acquisition module. The pressure-sensitive layer includes multiple microstructured pressure-sensitive modules embedded in the sensing units of the flexible PCB electrode layer. The multiple microstructured pressure-sensitive modules are connected by electrodes to form a flexible sensor array. An information acquisition module is used to receive and process the plantar pressure signal collected by the plantar flexibility sensor and convert the analog signal into a digital signal; The wireless communication module is used to transmit the processed digital signal to the terminal system; the terminal system is used to process the transmitted digital signal through a model combining CNN and LSTM, and output the detection results by connecting to the Internet platform.

[0007] Preferably, the flexible PCB board electrode layer of the plantar flexible sensor is divided into eight areas: the toe area, the middle of the metatarsal area, the outer side of the metatarsal area, the inner side of the metatarsal area, the outer side of the midfoot area, the inner side of the midfoot area, the outer side of the calcaneal area and the inner side of the calcaneal area; among them, the distribution density of the microstructure pressure-sensitive modules in the metatarsal area and the calcaneal area is higher than that in the midfoot area.

[0008] Preferably, the microstructured pressure-sensitive module of the pressure-sensitive layer is composed of a composite stack of a convex forming part, a printing film and a concave forming part, which is used to amplify local pressure changes and improve detection sensitivity.

[0009] Preferably, the information acquisition module uses a multi-channel ADC chip to achieve high-precision synchronous sampling, and reduces wire resistance fluctuations through integrated electrode design.

[0010] Preferably, the working principle of the terminal system is: The plantar pressure data is analyzed using a model combining CNN and LSTM. The spatial features of the plantar pressure data are extracted through the convolutional layer of CNN, and the feature map dimension is reduced through the pooling layer to retain important information. Finally, the convolutional feature map is flattened into a one-dimensional vector in the Flatten layer to provide input for the LSTM. Multiple LSTM units are used to process the spatial feature sequence extracted by CNN and capture the dynamic characteristics of the plantar pressure data over time. Finally, the Dense layer maps the LSTM output to the final task result, further analyzes the plantar pressure information, and outputs the detection results.

[0011] A method for preparing a smart insole for plantar pressure detection, for preparing any of the above-mentioned smart insole for plantar pressure detection, comprising the following steps: S1. Add silicone oil, carbon grease, graphene, and carbon nanotubes into a stirring tank and mix them, stirring to obtain a prefabricated electrode slurry. Add a curing agent and a catalyst into the stirring tank and stir to complete the preparation of the conductive slurry. S2. Pour SC320 potting material and PDMS solution onto the surface of the convex mold in sequence, and solidify them through secondary molding to form a convex molded part; S3, pouring PDMS solution on the surface of the convex mold and curing it to form a concave molded part; S4, overlapping the convex molding part, the concave molding part and the printing film to form a plurality of microstructure pressure-sensitive modules; S5. Select a 100-mesh screen, fix the printing film on the bottom of the screen printing plate, and clean it with alcohol; take an appropriate amount of conductive paste and place it outside the screen pattern; S6. Use a polyurethane scraper to apply the conductive paste at a uniform speed so that the conductive paste adheres tightly to the printing film; peel off the printing film, ventilate and cure, cut and package, and obtain a printed flexible sensor array; S7. Attach the printing die to the flexible PCB board, install multiple microstructure pressure-sensitive modules in sequence according to the pattern of the flexible PCB board, and then cover it with a layer of printing film. The double-layer printing film forms a protective layer to complete the preparation of the plantar flexible sensor; S8. Configure the corresponding information acquisition module and wireless communication module for the flexible sole sensor to obtain a smart insole.

[0012] Preferably, the mass ratio of silicone oil, carbon grease, graphene and carbon nanotubes added to S1 is 10:5:0.4:0.4; the specific method of stirring to obtain the prefabricated electrode slurry is: first vacuuming the planetary mixer, then setting the stirring mode parameters to 2200r / 180s, and stirring to obtain the prefabricated electrode slurry.

[0013] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: (1) The present invention uses screen printing to prepare an array of flexible sensors, which are personalized according to the user's personal characteristics. Combined with traditional Chinese medicine theory, the sole of the foot is divided into zones and the area where the sensors are distributed is planned, so as to accurately collect foot information and assist doctors in diagnosis and rehabilitation treatment.

[0014] (2) Compared with the static plantar pressure detection device, the smart insole used in the present invention can not only be attached to the body, but also monitor the pressure changes under different motion states in real time, collect and analyze plantar information, and provide timely feedback on user health information.

[0015] (3) The present invention designs a flexible PCB board as the electrode lead-out part of the sensor. During the construction of the sensor array, the hardware circuit can be simplified, which facilitates the high integration of the microstructure sensor and avoids the interference caused by the deformation of the electrode during the information acquisition process.

[0016] (4) The smart insole designed by the present invention can be directly placed on the surface of the insole during use. It is easy to operate and transmits information wirelessly through the Bluetooth module to achieve timely transmission of information. The application monitors the pressure distribution on the sole of the foot in real time, tracks foot health and gait changes, and records data, thereby obtaining important information and feedback about foot health. The learning model is used to analyze historical data and combine it with Internet information to assist doctors in diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A structural diagram of a smart insole for plantar pressure detection provided by the present invention; Figure 2 This is a diagram showing the electrode layer area division of the flexible PCB board of the flexible plantar sensor of the present invention; Figure 3 A flow chart for preparing the flexible plantar sensor of the present invention; Figure 4 This is a circuit diagram of the plantar flexible sensor array of the present invention; Among them, 1-plantar flexible sensor, 2-information acquisition module, 3-wireless communication module, 4-terminal system, 5-toe area, 6-middle of metatarsal area, 7-lateral side of metatarsal area, 8-medial side of metatarsal area, 9-lateral side of midfoot area, 10-medial side of midfoot area, 11-lateral side of calcaneal area, 12-medial side of calcaneal area. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 like Figure 1 As shown, the present invention provides an intelligent insole for plantar pressure detection, comprising: a plantar flexible sensor, an information acquisition module, and a wireless communication module; The flexible plantar sensor 1 includes a flexible PCB electrode layer, a pressure-sensitive layer, and a protective layer. It is used to collect plantar pressure signals and send them to an information acquisition module. The pressure-sensitive layer includes multiple microstructured pressure-sensitive modules embedded in the sensing units of the flexible PCB electrode layer. The multiple microstructured pressure-sensitive modules are connected by electrodes to form a flexible sensor array. Information acquisition module 2, used to receive and process the plantar pressure signal collected by the plantar flexibility sensor and convert the analog signal into a digital signal; The wireless communication module 3 is used to transmit the processed digital signal to the terminal system; the terminal system 4 is used to process the transmitted digital signal through a model combining CNN and LSTM, and output the detection results by connecting to the Internet platform.

[0022] Specifically, plantar pressure changes detected by plantar flexibility sensor 1 are transmitted to information collection system 2 for preliminary analysis. This information is then wirelessly transmitted via Bluetooth to mobile phone / computer terminal 4, where a model system learns the collected information. This information is then used to provide feedback on the user's health status through internet platforms and doctor-assisted diagnosis. By measuring the main stress-bearing areas of the foot, the plantar pressure distribution is reflected, providing a reliable diagnostic tool for clinical medicine.

[0023] The flexible plantar sensor 1 consists of a flexible PCB electrode layer, a pressure-sensitive layer, and a protective layer. The pressure-sensitive layer is embedded in the sensing unit of the flexible PCB electrode layer, and the various pressure-sensitive structures are connected through electrodes. The flexible PCB electrode layer has the advantages of good flexibility and excellent adhesion. The formed electrode layer greatly simplifies the circuit and solves the problems of wire resistance changes when the sensor is stretched and poor contact when connected to the terminal, thereby improving the accuracy of the data. The pressure-sensitive layer is composed of multiple microstructured pressure-sensitive modules, each of which is embedded in the flexible PCB and connected by circuit leads in the flexible PCB, forming an array of flexible plantar sensors, accurately feedback the force conditions of various parts of the plantar; the microstructured pressure-sensitive modules are composed of convex moldings, printing films, and concave moldings, which are stacked in sequence to amplify plantar pressure changes and ensure the accuracy of plantar information.

[0024] The protective layer consists of two layers of printing film, which are attached to the bottom layer of the flexible PCB board and the surface layer after the pressure-sensitive layer is installed. It is mainly to prevent the flexible PCB board from directly contacting the sole of the foot and causing damage caused by wear.

[0025] The pressure-sensitive layer utilizes flexible sensor units, which feature an array of microstructured pressure-sensitive modules. This composite structure, comprised of a convex molding, a printed film, and a concave molding, significantly enhances the sensitivity and accuracy of pressure detection. Its unique microstructure effectively amplifies local pressure changes, enabling high-resolution detection of minute pressure signals, significantly improving measurement accuracy and effectively reducing noise interference. Furthermore, the flexible sensor units utilize an arrayed distribution pattern, enabling multiple units to independently respond to pressure changes in different regions, providing precise feedback on the pressure distribution characteristics of the sole of the foot.

[0026] The flexible sensor unit is directly embedded in the flexible PCB electrode layer, leveraging its excellent flexibility and adhesion to perfectly adhere to the sole of the foot. The embedded electrode design integrates the pressure-sensitive unit directly into the flexible PCB circuit, significantly simplifying the complex wiring of traditional sensors and effectively solving the resistance change problem caused by wire stretching and deformation through the multi-layer flexible substrate stacking process. Its lightweight design enables perfect integration into insoles or smart shoes, achieving high-precision plantar pressure monitoring without compromising wearer comfort. This ensures high-fidelity transmission of pressure signals and seamless integration with footwear products, making it widely applicable in fields such as sports analysis and medical rehabilitation, greatly improving its usability.

[0027] The plantar flexible sensor 1 combines traditional Chinese medicine theory with the different bearing capacities of the plantar to divide the plantar into eight areas, namely the toe area 5, the middle of the metatarsal area 6, the lateral metatarsal area 7, the medial metatarsal area 8, the lateral midfoot area 9, the medial midfoot area 10, the lateral calcaneal area 11 and the medial calcaneal area 12. Figure 2 Combining the bone structure and the force applied to the sole of the foot, the midfoot area is subjected to the least force, so fewer microstructure pressure-sensitive modules are distributed. The metatarsal and calcaneal areas are subjected to greater force, so more microstructure pressure-sensitive modules are distributed for more accurate measurements.

[0028] The microstructured pressure-sensitive module of the plantar flexible sensor 1 is prepared using screen printing technology and micro-nano embossing technology. The flexible PCB board of the plantar flexible sensor is divided into arrays according to the pressure zones of the plantar, and is personalized according to the user's personal characteristics. At the same time, based on the good flexibility of the flexible PCB board, it can be fully attached to the sole of the user's foot, which not only meets the accuracy of data collection but also achieves the comfort of daily wear, thereby ensuring the performance and accuracy of the product. Figure 4 .

[0029] Information Acquisition Module 2, based on the TI ADS1298 multi-channel ADC and supporting high-precision synchronous sampling, receives and processes pressure signals collected by the pressure sensor module. It converts analog signals into digital signals, ensuring high-resolution and real-time data acquisition. This module supports multi-channel synchronous sampling, enabling simultaneous acquisition of pressure data from multiple subareas of the foot, providing comprehensive data support for subsequent analysis.

[0030] The overall structure of the information acquisition module 2 is light, thin, and compact, relying on the flexibility of the flexible PCB electrode layer to achieve perfect adaptation to the sole of the foot without affecting daily use. The integrated electrode design simplifies the circuit layout, solves the problems of wire resistance fluctuation and poor contact, and ensures the stability of signal transmission. In addition, the protective layer of the flexible sole sensor is made of wear-resistant flexible material, which not only isolates the sole from friction but also maintains natural contact between the sensor and the foot, improving long-term reliability. The design of the information acquisition system relies on a multi-layer flexible substrate stacking process and a miniaturized architecture to take into account high-precision pressure monitoring and wearable practicality, making it suitable for scenarios such as sports analysis and medical rehabilitation.

[0031] The wireless communication module 3 is used to transmit the processed information to the terminal system, and can adopt Bluetooth, WiFi, LoRa or Zigbee transmission.

[0032] Terminal system 4 is used to further analyze the data, connect to an internet platform, assist doctors in diagnosis, and provide health information. Based on historical user data, the terminal system uses a combined convolutional neural network (CNN) and long short-term memory (LSTM) model to analyze plantar pressure data, identify the user's gait type (e.g., normal, abnormal), predict potential health risks, and provide more responsive feedback.

[0033] The smart insole monitors the user's motion in real time, using a built-in flexible pressure sensor to collect changes in plantar pressure during standing, walking, and running. The flexible sensor is placed in the insole. The pressure information received by the flexible sensor is converted into a digital signal via an information collection system connected to the inner side of the calf. This signal is then transmitted via a Bluetooth module. A combined CNN and LSTM model is used. The convolutional layers of the CNN module extract the spatial features of plantar pressure. The pooling layer reduces the dimensionality of the feature map, retaining important information. Finally, the Flatten layer flattens the convolved feature map into a one-dimensional vector, providing input for the LSTM. Multiple LSTM units are used to process the sequence of spatial features extracted by the CNN, capturing the dynamic characteristics of plantar pressure over time. Finally, a Dense layer maps the LSTM output to the final task result, further analyzing the plantar pressure information to assist doctors in diagnosis and provide real-time feedback on the wearer's health.

[0034] Working Principle: The device fabricates a screen-printed microstructure array of flexible pressure sensors and installs them on insoles. The device transmits plantar signals to a mobile phone or computer via a Bluetooth module, enabling intuitive monitoring of plantar signals. Through wireless data transmission, it accurately records key data, such as the pressure distribution of the wearer's left and right feet, gait, and cadence, in real time. This provides comprehensive foot health information, helps assess the patient's condition, and assists physicians in diagnosing and evaluating rehabilitation outcomes. Furthermore, the smart insole design utilizes flexible sensors that adhere to the wearer's body, making it portable and stable. Different flexible sensors offer different characteristics, meeting the needs of people of different age groups for sports monitoring and health management.

[0035] Example 2 The preparation method of the smart insole for plantar pressure detection in the present invention comprises the following detailed steps: Step 1: Use a balance to weigh 10g of silicone oil and add it to a stirring tank. Then add 5g of carbon grease, 0.4g of graphene, and 0.4g of carbon nanotubes to the stirring tank.

[0036] Step 2: First, vacuum the planetary mixer and then set the stirring mode parameters to 2200r / 180s to obtain the prefabricated electrode.

[0037] Step 3: Add 2g of curing agent into the mixing tank using a disposable dropper, continue to vacuum the planetary mixer, and then set the stirring mode parameters to 2200r / 120s to ensure that the two are fully uniform.

[0038] Step 4: Take out the stirring tank and add 20μL (or a few drops) of catalyst using a pipette (or medical syringe), and also vacuum and stir at 2000r / 30s.

[0039] Step 5: Pour the mixed SC320 potting material and PDMS solution into the surface of the convex mold in sequence, and perform the molding at 80°C for 2 hours and 100°C for 1 hour to form a convex molded part.

[0040] Step 6: Pour PDMS solution onto the surface of the convex mold and cure it at 100°C for 1 hour to form a concave molded part.

[0041] Step 7: The convex molding part and the concave molding part are overlapped with the printing mold to form a microstructure pressure-sensitive module.

[0042] Step 8: Select a 100-mesh screen, place the printing film on the bottom of the screen printing plate, and clean the printing film with alcohol.

[0043] Step 9: Weigh an appropriate amount of evenly mixed conductive ink and place it on the screen printing plate about 5 mm away from the printed pattern.

[0044] Step 10: Use a polyurethane rubber scraper to scrape at a constant speed of 10 mm / s, pressing the ink onto the screen pattern while scraping, and repeat this process 5 times to ensure that the conductive ink adheres tightly to the printed film according to the designed pattern.

[0045] Step 11: Peel off the printing film and place it in a ventilated and dry place to cure for 24 hours, then cut and package. Figure 3 shown.

[0046] Step 12: After curing, stick the printing die on the flexible PCB board, install multiple microstructure pressure-sensitive modules in sequence according to the pattern of the flexible PCB board, and then cover it with a layer of printing film as a protective film to complete the production of the plantar flexible sensor. Figure 4 Shown is a circuit diagram of a flexible sensor array.

[0047] Step 13: Configure the corresponding information acquisition module and wireless communication module for the plantar flexible sensor to obtain a smart insole.

[0048] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0049] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A smart insole for plantar pressure detection, characterized in that: include: Plantar flexible sensor, information collection module and wireless communication module; The plantar flexible sensor comprises a flexible PCB electrode layer, a pressure-sensitive layer and a protective layer, and is used to collect plantar pressure signals and send the plantar pressure signals to the information acquisition module; The pressure-sensitive layer includes a plurality of microstructured pressure-sensitive modules, which are embedded in the sensing units of the electrode layer of the flexible PCB board, and the plurality of microstructured pressure-sensitive modules are connected through electrodes to form a flexible sensor array; The information acquisition module is used to receive and process the plantar pressure signal collected by the plantar flexibility sensor and convert the analog signal into a digital signal; The wireless communication module is used to transmit the processed digital signal to the terminal system; the terminal system is used to process the transmitted digital signal through a model combining CNN and LSTM, and output the detection result by connecting to the Internet platform.

2. The smart insole for plantar pressure detection according to claim 1, characterized in that: The flexible PCB electrode layer of the plantar flexible sensor is divided into eight areas: the toe area, the middle of the metatarsal area, the outer side of the metatarsal area, the inner side of the metatarsal area, the outer side of the midfoot area, the inner side of the midfoot area, the outer side of the calcaneal area and the inner side of the calcaneal area; among them, the distribution density of the microstructure pressure-sensitive modules in the metatarsal area and the calcaneal area is higher than that in the midfoot area.

3. The smart insole for plantar pressure detection according to claim 1, characterized in that: The microstructured pressure-sensitive module of the pressure-sensitive layer is composed of a composite stack of a convex forming part, a printing film and a concave forming part, and is used to amplify local pressure changes and improve detection sensitivity.

4. The smart insole for plantar pressure detection according to claim 1, characterized in that: The information acquisition module uses a multi-channel ADC chip to achieve high-precision synchronous sampling and reduces wire resistance fluctuations through integrated electrode design.

5. The smart insole for plantar pressure detection according to claim 1, characterized in that: The working principle of the terminal system is as follows: The plantar pressure data is analyzed using a model combining CNN and LSTM. The spatial features of the plantar pressure data are extracted through the convolutional layer of CNN, and the feature map dimension is reduced through the pooling layer to retain important information. Finally, the convolutional feature map is flattened into a one-dimensional vector in the Flatten layer to provide input for the LSTM. Multiple LSTM units are used to process the spatial feature sequence extracted by CNN and capture the dynamic characteristics of the plantar pressure data over time. Finally, the Dense layer maps the LSTM output to the final task result, further analyzes the plantar pressure information, and outputs the detection results.

6. A method for preparing a smart insole for plantar pressure detection, for preparing the smart insole for plantar pressure detection according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Add silicone oil, carbon grease, graphene, and carbon nanotubes into a stirring tank and mix them, stirring to obtain a prefabricated electrode slurry. Add a curing agent and a catalyst into the stirring tank and stir to complete the preparation of the conductive slurry. S2. Pour SC320 potting material and PDMS solution onto the surface of the convex mold in sequence, and solidify them through secondary molding to form a convex molded part; S3, pouring PDMS solution on the surface of the convex mold and curing it to form a concave molded part; S4, overlapping the convex forming part, the concave forming part and the printing film to form a plurality of microstructure pressure-sensitive modules; S5. Select a 100-mesh screen, fix the printing film on the bottom of the screen printing plate, and clean it with alcohol; take an appropriate amount of conductive paste and place it outside the screen pattern; S6. Use a polyurethane scraper to apply the conductive paste at a uniform speed so that the conductive paste adheres tightly to the printing film; peel off the printing film, ventilate and cure, cut and package, and obtain a printed flexible sensor array; S7. Attach the printing die to the flexible PCB board, install multiple microstructure pressure-sensitive modules in sequence according to the pattern of the flexible PCB board, and then cover it with a layer of printing film. The double-layer printing film forms a protective layer to complete the preparation of the plantar flexible sensor; S8. Configure the corresponding information acquisition module and wireless communication module for the flexible sole sensor to obtain a smart insole.

7. The method for preparing a smart insole for plantar pressure detection according to claim 6, characterized in that: The mass ratio of silicone oil, carbon grease, graphene and carbon nanotubes added to S1 is 10:5:0.4:0.4; the specific method of stirring to obtain the prefabricated electrode slurry is: first vacuuming the planetary mixer, then setting the stirring mode parameter to 2200r / 180s, and stirring to obtain the prefabricated electrode slurry.

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