Insole type pressure-shear force sensor for early warning of sole ulcer of diabetic patient

Abstract

The invention discloses an insole type pressure-shear force sensor for early warning of sole ulcer of a diabetic patient, and belongs to the technical field of electronic skin. The device comprises a pressure sensing layer, a shear force sensing layer and a processing and transmission system, the pressure sensing layer comprises a plurality of pressure sensor units distributed in an array mode, and each pressure sensor unit works based on a piezoresistive effect principle; the shear force sensing layer is positioned above the pressure sensing layer and comprises a plurality of distributed capacitive sensors; the pressure sensing layer and the shearing force sensing layer are electrically connected with the adapter plate respectively so as to summarize pressure data and shearing force data, and then the adapter plate is connected with the processing and transmitting system. The device can accurately measure the pressure and shear force of the foot sole of the diabetic patient in daily activities in real time and feed back data, so that abnormity can be found in time, the occurrence risk of foot sole ulcer can be prevented and reduced, and effective technical support is provided for foot health management of the diabetic patient.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic skin, and particularly relates to a shoe-pad type pressure-shear force sensor for early warning of foot bottom ulcer of a diabetic patient. BACKGROUND

[0002] As a common chronic disease, diabetes causes many complications that seriously threaten the health of patients. Among them, diabetic foot is one of the common and serious complications of diabetes, and foot bottom ulcer is an important manifestation in the development process of diabetic foot. According to relevant medical research, about 15%-25% of diabetic patients will develop foot ulcer during the course of the disease. Once it occurs, it is difficult to heal, and the risk of amputation is significantly increased.

[0003] In the prior art, there are many deficiencies in the monitoring means for the foot bottom condition of diabetic patients. Traditional foot bottom pressure measuring equipment, such as some piezoresistive or capacitive flexible sensors, can only measure the foot bottom pressure, and cannot provide shear force data. However, research has confirmed that shear force is one of the important factors leading to foot bottom ulcer in diabetic patients. For example, during daily walking, there is not only vertical pressure between the foot bottom and the inner surface of the shoe, but also horizontal shear force. Long-term abnormal shear force is easy to damage the foot bottom skin tissue, and then induce ulcer. And most of these devices often need to be used by patients in a specific test environment, making it difficult to realize real-time monitoring in daily activities. In clinical practice, due to the lack of comprehensive and real-time monitoring of foot bottom pressure and shear force, doctors have difficulty in accurately judging the risk of foot bottom ulcer in patients, thereby affecting the early intervention and treatment effect.

[0004] Therefore, it is urgent to provide a shoe-pad type pressure-shear force sensor for early warning of foot bottom ulcer of a diabetic patient. SUMMARY

[0005] The purpose of the present application is to overcome the defects in the prior art and provide a shoe-pad type pressure-shear force sensor for early warning of foot bottom ulcer of a diabetic patient. The device of the present application can measure the pressure and shear force of the foot bottom of a diabetic patient in daily activities in real time and accurately, and feed back the data in order to discover abnormalities in time, prevent and reduce the risk of foot bottom ulcer, and provide effective technical support for foot health management of diabetic patients.

[0006] The specific technical solutions adopted by the present application are as follows:

[0007] The present application provides a shoe-pad type pressure-shear force sensor for early warning of foot bottom ulcer of a diabetic patient, comprising a pressure sensing layer, a shear force sensing layer and a processing and transmission system.

[0008] The pressure sensing layer comprises a plurality of arrayed pressure sensor units, each of which works based on the piezoresistive effect principle; the pressure data are obtained by measuring the change of the resistance value in the pressure sensor unit;

[0009] The shear force sensing layer is located above the pressure sensing layer and comprises a plurality of distributed capacitive sensors; the size and direction of the shear force are obtained by measuring the change of the capacitance value in the capacitive sensor;

[0010] The pressure sensing layer and the shear force sensing layer are electrically connected with the adapter plate to realize the collection of the pressure data and the shear force data, and the adapter plate is then connected with the processing and transmission system;

[0011] The processing and transmission system is used for processing the collected electrical signals and transmitting the processed data to the upper computer in real time.

[0012] Preferably, the pressure sensing layer and the shear force sensing layer are both made of flexible materials.

[0013] Preferably, the flexible material is a pet film.

[0014] Preferably, in the pressure sensing layer, more dense pressure sensor units are arranged at the positions corresponding to the heel, the forefoot and the toes.

[0015] Preferably, the capacitive sensor comprises a fixed lower plate and a movable upper plate; when the shear force is generated due to the relative displacement of the foot bottom, the movable plate can move synchronously with the foot bottom, so that the distance or the overlapping area between the fixed plate and the movable plate changes, resulting in the change of the capacitance value.

[0016] Preferably, the processing and transmission system comprises a signal processing module and a data transmission module.

[0017] The signal processing module is electrically connected with the adapter plate and is used for sequentially amplifying, filtering and analog-digital converting the collected electrical signals; the signal processing module is then connected with the data transmission module, and the data transmission module is used for transmitting the processed data to the external upper computer in real time through wireless communication technology.

[0018] Preferably, the wireless communication technology comprises Bluetooth and Wi-Fi.

[0019] Preferably, the upper computer comprises a smart phone, a smart bracelet or a remote medical monitoring platform.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1) The present application can simultaneously measure plantar pressure and shear force, providing more comprehensive plantar mechanics information than traditional devices that can only measure pressure, which helps to more accurately assess the risk of plantar ulceration in diabetic patients.

[0022] 2) The present application can achieve real-time monitoring in daily activities through wireless data transmission function, without the need for patients to perform detection in a specific environment, which is convenient and fast, and can timely capture the changes in plantar mechanics, providing the possibility for early intervention. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a flowchart of the method of the present application;

[0024] Figure 2 is a pressure test result graph in the example;

[0025] Figure 3 is a structural schematic diagram of the right foot pressure sensing layer in the example;

[0026] Figure 4 is a structural schematic diagram of the right foot shear force sensing layer in the example;

[0027] Figure 5 is a structural schematic diagram of the adapter plate in the pressure-shear force sensor in the example;

[0028] Figure 6 is a schematic diagram of the processing and transmission system in the example; wherein (a) is a rechargeable power supply module, (b) is a power stabilizing module, (c) is a multi-channel selection switch module, and (d) is a power switching module. DETAILED DESCRIPTION

[0029] The present application will be further described and explained with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment in the present application can be combined accordingly without conflict.

[0030] The present application provides a shoe pad type pressure-shear force sensor for early warning of plantar ulceration in diabetic patients, which mainly comprises a pressure sensing layer, a shear force sensing layer and a processing and transmission system.

[0031] As a preferred embodiment of the present application, the pressure sensing layer and the shear force sensing layer are both made of flexible material to ensure comfort and close fit to the plantar surface for accurate sensing of pressure and shear force changes. The flexible material can be a pet film, of course, other flexible materials can also be selected according to actual conditions.

[0032] The components of the present application will be described in detail below.

[0033] In the device of the present application, the pressure sensing layer comprises a plurality of pressure sensor units which work on the principle of piezoresistive effect. When the foot bottom applies pressure to the insole-type pressure-shear force sensor of the present application, the resistance value of the pressure sensor unit will change, and the pressure data can be obtained by measuring the change of the resistance value of the pressure sensor unit.

[0034] As a preferred embodiment of the present application, the pressure sensor units are arranged in an array, which can accurately perceive the pressure distribution of different areas of the foot bottom. For example, more densely arranged sensor units are arranged in the pressure-sensitive parts such as the heel, forefoot and toes, so as to improve the accuracy of pressure detection. As shown in Figure 3 The structure diagram of the right foot pressure sensing layer provided in a preferred embodiment of the present application is shown in FIG. 2. As can be seen from the figure, the sensor designed in the form of insole can be put into the patient's shoes, which is convenient for real-time monitoring in daily life.

[0035] In the device of the present application, the shear force sensing layer is located above the pressure sensing layer, and its working principle is based on the change of capacitance. The layer is composed of a plurality of capacitive sensors, each of which comprises a fixed plate and a movable plate. When the relative displacement of the foot bottom generates shear force, the movable plate will move, thereby changing the distance or overlapping area between the two plates of the capacitor, resulting in a change in the capacitance value. By detecting the change amount of the capacitance value, the size and direction of the shear force can be accurately calculated. For example, in the areas such as the arch which are easily affected by shear force, the capacitive sensors are arranged reasonably to improve the detection sensitivity of shear force. As shown in Figure 4 The structure diagram of the right foot shear force sensing layer provided in a preferred embodiment of the present application is shown in FIG. 3. As can be seen from the figure, the sensor designed in the form of insole can be put into the patient's shoes, which is convenient for real-time monitoring in daily life.

[0036] In the device of the present application, the pressure sensing layer and the shear force sensing layer are respectively electrically connected with the adapter plate, and the adapter plate is used to realize the collection of pressure data and shear force data.

[0037] As a preferred embodiment of the present application, the structure diagram of the adapter plate provided in a preferred embodiment of the present application is shown in FIG. 4. As can be seen from the figure, the collected pressure and shear force data are collected into the signal processing system. Figure 5

[0038] In the device of the present application, the adapter plate is then connected with the processing and transmission system. The processing and transmission system is used to process the collected electrical signals and transmit the processed data to the upper computer in real time.

[0039] ​As a preferred embodiment of the present application, the processing and transmission system mainly includes a signal processing module and a data transmission module. The signal processing module is electrically connected with the adapter plate, responsible for collecting the electrical signals output by the pressure sensor unit and the capacitive sensor, and sequentially performing amplification, filtering, analog-to-digital conversion and other processing on these signals. The processed digital signals are further analyzed and calculated to obtain accurate pressure and shear force data. For example, advanced algorithms are used to denoise the collected signals to improve the accuracy and stability of the data. The signal processing module is then connected with the data transmission module, which can transmit the processed pressure and shear force data to external devices (i.e. host computers such as smartphones, smartwatches or remote medical monitoring platforms) in real time through wireless communication technology (such as Bluetooth, Wi-Fi, etc.). Patients or medical personnel can intuitively view the plantar pressure and shear force data through the corresponding application program or software, and determine whether there is an abnormal situation according to the preset threshold value.

[0040] As a preferred embodiment of the present application, the processing and transmission system mainly includes STM32H750VBT6, a rechargeable power module, a power switching module, a power stabilizing module, a multi-channel selection switch module, a WIFI module, a Bluetooth module, etc. Among them, STM32H750VBT6, the rechargeable power module, the power switching module, the power stabilizing module, and the multi-channel selection switch module belong to the signal processing module, and the WIFI module and the Bluetooth module belong to the data transmission module. As shown in FIG. 6, a partial module schematic diagram of the processing and transmission system is shown, including a rechargeable power module (a), a power stabilizing module (b), a multi-channel selection switch module (c), and a power switching module (d).

[0041] The core master control of the processing and transmission system adopts STM32H750VBT6, which has a high-performance Cortex-M7 core with high computing speed and low power consumption characteristics, and can efficiently process the multi-channel signals collected by the pressure-shear force sensing layer. The rechargeable power module is used to ensure continuous power supply. The power switching module is used to realize intelligent switching between external power supply (such as USB access) and battery power supply. The power stabilizing module provides stable voltage (such as 3.3V, 5V, etc.) for STM32, sensors and communication modules, avoiding voltage fluctuations affecting signal accuracy. The multi-channel selection switch module can adapt to the plantar multi-region pressure-shear force sensor array, select the signal channel according to the demand, and improve the collection efficiency. The WIFI module and the Bluetooth module are responsible for wirelessly transmitting the processed plantar mechanics data to mobile phones, medical terminals, etc., for real-time monitoring and data analysis.

[0042] In actual use, the system first pre-processes the original signal (taking pressure as an example), that is, it uses sliding average filtering to remove high-frequency jitter from the collected original pressure signal and retain the true pressure fluctuation characteristics. According to the pressure baseline in the resting state, the threshold is dynamically set to filter out environmental interference and sensor zero drift. Secondly, pressure feature extraction is performed. Parameters such as peak pressure, average pressure, and pressure gradient are extracted to quantify the force intensity of the plantar. Then there is an ulcer risk assessment model. A hierarchical warning mechanism is adopted: based on the pressure distribution characteristics, a multi-level risk model is established (such as Figure 1 As shown): Green (safe); Yellow, Orange (concern): indicate potential friction risks; Red (warning): triggers a real-time alert.

[0043] Similarly, the treatment of shear force is the same as the above-mentioned pressure treatment method, which will not be repeated here.

[0044] The insole type pressure-shear force sensor for warning diabetic patients of plantar ulcers of the present invention is used in actual use as follows: Figure 1 That is, the user first wears the device, and then when the user stands still or walks, the pressure sensing layer and the shear force sensing layer generate corresponding pressure or shear force. The generated signal enters the signal processing module and is then transmitted to the terminal through the data transmission module.

[0045] like Figure 2 FIG2 is a diagram showing the pressure test results obtained in a preferred embodiment of the present invention when the device is actually used. As can be seen from the figure, the device of the present invention can obtain relatively good and accurate pressure values ​​and the force applied to the foot.

[0046] The embodiment described above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent substitution or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. A shoe insole type pressure-shear force sensor for warning of plantar ulcers in diabetic patients, characterized by: It includes a pressure sensing layer, a shear force sensing layer and a processing and transmission system; The pressure sensing layer includes a plurality of pressure sensor units distributed in an array, each of which operates based on the piezoresistive effect principle; pressure data is obtained by measuring the change in resistance value in the pressure sensor unit; The shear force sensing layer is located above the pressure sensing layer and includes a plurality of distributed capacitive sensors; the magnitude and direction of the shear force are obtained by measuring the change in the capacitance value of the capacitive sensors; The pressure sensing layer and the shear force sensing layer are respectively electrically connected to an adapter plate to achieve aggregation of pressure data and shear force data, and the adapter plate is subsequently connected to a processing and transmission system; The processing and transmission system is used to process the collected electrical signals and transmit the processed data to the host computer in real time.

2. The insole-type pressure-shear force sensor for warning of plantar ulcers in diabetic patients according to claim 1, characterized in that: The pressure sensing layer and the shear force sensing layer are both made of flexible materials.

3. The insole-type pressure-shear force sensor for warning of plantar ulcers in diabetic patients according to claim 2, characterized in that: The flexible material is a PET film.

4. The insole-type pressure-shear force sensor for warning of plantar ulcers in diabetic patients according to claim 1, characterized in that: In the pressure sensing layer, more dense pressure sensor units are arranged at corresponding positions of the heel, forefoot and toes.

5. The insole-type pressure-shear force sensor for warning of plantar ulcers in diabetic patients according to claim 1, characterized in that: The capacitive sensor includes a fixed electrode located at the bottom and a movable electrode located at the top; when the sole of the foot undergoes relative displacement and generates shear force, the movable electrode can move synchronously with the sole of the foot, thereby changing the distance or overlapping area between the fixed electrode and the movable electrode, resulting in a change in the capacitance value.

6. The insole-type pressure-shear force sensor for warning of plantar ulcers in diabetic patients according to claim 1, characterized in that: The processing and transmission system includes a signal processing module and a data transmission module; The signal processing module is electrically connected to the adapter board and is used to amplify, filter and perform analog-to-digital conversion on the collected electrical signals in sequence; the signal processing module is then connected to the data transmission module, which is used to transmit the processed data to an external host computer in real time through wireless communication technology.

7. The insole-type pressure-shear force sensor for warning of plantar ulcers in diabetic patients according to claim 6, characterized in that: The wireless communication technology includes Bluetooth and Wi-Fi.

8. The insole-type pressure-shear force sensor for warning of plantar ulcers in diabetic patients according to claim 6, characterized in that: The host computer includes a smart phone, a smart bracelet or a remote medical monitoring platform.

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