The Orthosis Design Method Study Based On Digital Foot And Calf Model

Orthotics is an important tool to prevent or correct deformities of limbs and trunk,or to treat joint and neuromuscular diseases and to compensate their functions.It is of great significance to the rehabilitation of patients in clinical practice.However,most of the existing orthotics are mass-produced products,which can’t meet the individual shape characteristics of patients,resulting in poor matching,low satisfaction,low efficiency and other problems,affecting the rehabilitation effect of patients.Therefore,improving the matching degree of orthopedic products and improving the user satisfaction become the focus and purpose of this research in this paper.Parametric design is widely used in architectural design,mechanical design and product design because of its fast,accurate and convenient characteristics.Based on the data of reverse engineering,this paper builds a parametric model of calf and foot,and a design method of orthosis based on parametric calf and foot model,which is applied to orthosis design.The main contents of the study are as follows:First of all,using the reverse engineering technology to build the calf and foot model database,build the calf and foot parametric model by using regression analysis.The calf and foot data of 83 subjects were collected by 3D scanning technology.The data were preprocessed and the statistical shape model was obtained by consistent processing.Based on the principal component analysis and regression analysis,the parametric model of calf and foot is built,and its error analysis is carried out.Then,an orthotic design method based on the parametric leg plus foot model is constructed.Using analytic hierarchy process to obtain the user demand priority,using TRIZ conflict resolution principle to obtain the innovative design direction,then the parametric modeling of orthotics is processed based on the leg plus foot parametric model,the design alternative of orthotics is obtained combined with the innovative design direction.Finally,the subjective evaluation method based on Fuzzy AHP and the objective evaluation method of orthosis matching index are constructed.After wearing the 3D printed orthotics,the patient used the satisfaction score table constructed by fuzzy analytic hierarchy process to evaluate the design scheme subjectively.Using the matching index to evaluate the orthotics objectively.The results show that the design of orthosis based on calf and foot parametric model achieves higher user satisfaction and matching degree.In this study,reverse engineering,parametric modeling technology and TRIZ theory are applied to the design of orthosis.A case of the hallux valgus orthosis design is conducted to demonstrate the proposed method can realize the rapid and accurate customization of orthosis products,and improve the matching degree and satisfaction degree of orthosis,and provide a better solution for the design of orthosis according with Ergonomics.