Design And Experimental Study Of Foot Orthosis And Piezoelectric Energy Capture Integrated System

Foot is an important part of human body and closely related to human life and health.The customization of orthotics can be a good solution to all kinds of foot problems,but the complicated and high cost of functional insoles customization process is daunting.At the same time,some 3D printed orthotics have entered clinical trials or formed products and entered the market,showing a good prospect for development.Compared with traditional orthotic manufacturing methods,3D printing technology can effectively simplify the manufacturing process and improve the overall performance,which is the mainstream development direction of future orthotic preparation.With the further development of the information society,orthotics will also become intelligent.For example,sensors will be added to assess the user’s usage and health status.Such sensors can use the energy generated by the human body to self-power.In this paper,simulation analysis technology is used to replace the traditional customization process.By establishing the coupling model of foot-orthotic-ground,three kinds of materials commonly used in 3D printing orthotics are selected to obtain the condition of human plantarus pressure through numerical simulation,and the effect of orthotic is estimated in advance through finite element simulation,and compared with the experimental results in the later stage,so as to verify the rationality of the preliminary design.At the same time,the foot energy capture device is designed.The device can be placed in the heel of the shoe to convert the mechanical energy of human walking into electric energy,so as to replace the battery and realize the self-power supply of electronic products such as smart wearable devices and intelligent monitoring devices.The research content of this paper is as follows:(1)Parametric design of orthotics.With the help of reverse engineering,the complete foot model of the patient was established.According to the classification of the medically defined arch region,the Geomagic,Rhino,Matlab and Solid Works software was used to extract the point cloud model of the patient’s arch region.With the plantar stress optimization as the design criteria,the model was further reconstructed using NURBS curves and surfaces.According to the optimal height of the arch,the thickness of the orthopedic device was properly compensated,and the surface was modified into the solid model of the whole foot orthotic device by using modeling software.Then the finite element model could be further established based on this model.(2)Design of foot energy capture device.Based on this,a mathematical model is established for the piezoelectric cantilever composed of single piezoelectric wafers,and the reasonable size parameters of the mathematical model are analyzed to determine the excitation scheme.In the design of mechanical mechanism,the foot displacement during walking is converted into reciprocating circular motion,and the whole large numerical displacement is decomposed into small displacement through the excitation gear.The teeth of the gear move the piezoelectric cantilever beam,and then the cantilever beam structure is continuously excited to achieve the purpose of converting mechanical vibration into electric energy.(3)Analyze the influence of materials on the function of orthotics.A composite finite element model of foot-orthotic-ground was established,and the model was used to analyze the state of human feet standing and equivalent stress changes of orthotics when wearing orthotics of different materials,so as to reflect the influence of materials on the comfort level of orthotics.At the same time,foot comfort values of orthotics of different materials were calculated based on the comfort function of plantar pressure distribution,and compared with the simulation analysis results.(4)System function and experimental verification.Based on the related data of foot pressure and gait obtained from foot pressure and gait experiments,the variation rule of data before and after wearing orthopedic devices of different materials was analyzed,and the rationality and effectiveness of the design of orthopedic devices was verified by referring to the subject’s subjective evaluation.In the experimental aspect of piezoelectric energy harvesting device,the production of piezoelectric energy harvesting device is completed and the open-circuit output voltage of the device is tested to verify the function of the energy harvesting device.