Research On Plantar Pressure Distribution Based On Flexible Tactile Sensor

In recent years,the rapid development of flexible electronics has become an important innovation in the future biomedical field.flexible tactile sensors have a disruptive effect on wearable medical devices.Plantar pressure distribution can reflect foot injuries or lesions,and was widely used in health monitoring and medical diagnosis.However,it was often limited by the shortcomings of detection equipment that are not portable and expensive,and therefore it was not widely used.To overcome the above problems,the application of a flexible tactile sensor on detecting some pressure distribution of the plantar was proposed.Flexible tactile sensors have the advantages,like softness,stretchable,and better adhesion.However,most of the current sensors with excellent performance cannot be readily applied because of the high processing cost,small detection range,and fragility.To this end,this paper used conductive fabrics and microporous membranes to make capacitive flexible tactile sensors and further made smart insoles to solve the above problems.In this paper,the ionic liquid 1-butyl-3-methylimidazole hexafluorophosphate is used to activate the microporous membrane to obtain an active dielectric layer.After assembling with the fabric electrode,an ionic capacitive flexible tactile sensor composed of a sandwich structure is formed.The device was optimized by adjusting the loading of ionic liquid.The sensitivity of the device is 0.14 k Pa-1 at 0-25 k Pa,and decreases to 0.012 k Pa-1 at 25-300 k Pa.The response time of the device is less than 100 ms,it can generate feedback for pressures above 20 Pa,and can withstand 3000 cycles of loading to maintain stability.In addition,the device has the characteristics of simple preparation process,easy availability of raw materials and low cost,which solves the problems of high price and low production efficiency in practical applications.Plantar pressure distribution was divided into six zones,and installed 25 of the above sensors in a single foot area to make a smart insole.In the experiment,the plantar pressure distribution in different postures was collected,and the plantar pressure distribution and pressure center point during static standing can be used as biometric identification signals.It was verified that forefoot and heel are the main load-bearing areas of plantar pressure,accounting for 91% of the total pressure.The gait process was calibrated through the detection of the changes in plantar pressure during the gait process.The results of gait analysis using smart insoles have broad application value in gait training and machine exoskeleton manipulation.In addition,the plantar pressure distribution under two different rehabilitations training modes were detected,and the changes in the plantar pressure distribution during the movements from standing position to sitting position to standing position and turning left and right were analyzed.In summary,the research on the intelligent insole based on the flexible tactile sensor and its application to the measurement of the pressure distribution of the plantar are of great significance and practical value.