Design And Analysis Of Insole Based On Flexible Hall Unit For Dynamic Perceiving Of Distributed Force And Displacement

In this thesis,a kind of flexible insole based on Hall sensor unit is designed,which can dynamically monitor the distributed force and displacement information of the human sole.Compared with the traditional pressure sensor,the sensor can simultaneously measure the force and displacement of two modes information,and has the advantages of high measurement accuracy,large deformation range,modular design,low production cost..The output voltage of Hall sensor can reflect the pressure and the deformation of the flexible body quantitatively by constructing the inverse solution model.Based on this principle,through theoretical calculation,numerical analysis and finite element simulation,the structure design and rapid prototyping manufacturing of the flexible Hall sensor unit were completed,and the performance test and calibration experiment were carried out.The results show that the sensor has good linearity,the consistency error is less than 1N,and the maximum repetition error is only 1%.Then BP neural network is used to correct the return error of the sensor,and the accuracy of the sensor is further improved.Based on the material characteristics of the flexible body in the flexible Hall sensor unit,a zoned dynamic force monitoring insole measurement system was designed,including the pad hardware structure,signal acquisition and processing system and human-computer interaction system.The structure of the insole is generally divided into upper and lower layers.19 flexible Hall sensing units are arranged in 5 measuring areas between the soft bottom layer of the insole base and the wear-resistant bottom seat of the insole.The data acquisition and processing part is mainly realized by the STM32F103 system board.On this basis,the analog switch is added to increase the number of acquisition channels,and the stable acquisition of sensor signals is realized by the voltage regulator module.Using Bluetooth module to achieve wireless transmission function.Then the human-computer interaction interface is designed by using Qt.The performance of the prototype was experimented and analyzed at last.Several participants wore insole and performed static and dynamic experiments to compare their results on a commercially available Zebris force measuring tablet in Germany.Among them,under static condition,the error in the metatarsal and heel regions with the largest proportion of plantar pressure was 1.909% and 0.429% for the test subjects with the most similar foot size and insole size.In the dynamic sit-to-station experiment,the variation trend of foot force under the two devices was consistent,which verified the accuracy and validity of the pad data.The dynamic monitoring insole of distributed pressure measurement can not only obtain the information of plantar pressure dynamically and in real time for gait analysis,but also obtain the dynamic change information of the foot arch height.