Insole Design Method Research Based On Foot Shape And Plantar Pressure Distribution

Feet are often called another heart of a man. The feet support the weight of our body. Besides, they also act as a lever when we are walking or jogging. However perennially aberrant pressure may cause pathological changes in foot, such as diabetic foot ulcers. Foot pressure distribution is closely related to our foot health. What contacts with plantar most closely is the insole. In clinical medicine field, insole is often used as a conservative treatment program in curing or preventing pathological changes in foot because insoles may influence the force on plantar for a long time which do not require performing operations or taking medicines. However, the insoles on the market at present are made together in accordance with a unified certain type without taking individual differences into account. As a result, customized insoles which depend on the individual’s feet shapes and plantar pressure are eager to be designed in order to meet the needs of different groups. This paper proposes a design method based on feet shapes and plantar pressure which aims at improving design method deficiencies of the prior insoles and market demands. The main research work of this paper is summarized as follows:Firstly, study the method of establishing initial model about foot and customized insoles. Obtain the point cloud model of the feet through 3D scanner and then establish geometric model of the feet and insole through reverse engineering software. After that, the geometric model is imported into the Finite element analysis software to establish the finite element model. This step accomplishes the work about the initial geometric model and finite element model establishment of customized insole.Secondly, study the contact process of the feet and insole; analyze plantar pressure distribution and then extract the plantar pressure data. Analyze the finite element method for solving contact problems theoretically. The contact process of foot and insole in the static standing situation is simulated by the contact analysis module of the finite element software ANSYS. According to the results of simulation analysis, the plantar pressure data is extracted by APDL language.Thirdly, in order to solve the existing lack of partial adjustment methods on insole, the entire surface of the insole is adjusted by Laplace deformation technology and then the optimization insole design is completed. At first, the mapping relation between different topological adjacency is successfully worked out and the nodes’ equivalent stress on the triangular mesh vertices is obtained. After that, the mapping relation between plantar pressure and surface irregularities of the insole is established. The best insole has been obtained after several times of shape adjustment with the Laplace morphing technique which is based on the result of finite element analysis.Finally, human experiments show the results of the best insole in plantar pressure redistribution. Through the comparative analysis of three experiments which use the F-Scan insole plantar pressure measurement system and comparative analysis with the findings of other scholars, plantar pressure redistribution of the best insole compared to other optimization insoles has been verified.