Mathematical Modeling of Gait for Lower Limb Exoskeleton

Abstract

This study presents the mathematical Modeling of gait. This model is for the lower limb exoskeleton. The exoskeleton has wide scope in hospitals, physical training, and army. The comfortable gait with exoskeleton requires a good mathematical model of gait. This Modeling of this study starts with a C3D file which is taken from a hospital. This Modeling uses MLS viewer, MOKKA, Any Body, and Matlab software. The basic information of the C3D file read with the MLS viewer software. This software tells the type of force plate, name of maker points, the number of force plate and marker points use in the gait analysis. The motion of marker points visualizes in MOKKA software. These visuals in MOKKA software give the position of all marker points. The MOKKA software also gives information about the starting frame number and last frame number for the gait on the force plates. The information collected from the MLS viewer and MOKKA software uses for modification of Any Script of the inbuilt model of Any Body software. The kinematic and inverse dynamic analysis of C3D file data performs in Any Body software after proper changes in Any Script of the model. The linear position and velocity data obtained from kinematic analysis use in Mat lab Modeling. Mat lab Modeling has two-step: curve fitting and curve plotting. The sum of sine equation fits on this linear position and velocity data using the curve fitting app of Mat lab. Another velocity equation is evaluated by the differentiation of the position equation. These equations of linear position and velocity simulate using Mat lab software. The plot of kinematic analysis data and plot of modeled equations compare in the Mat lab software. The goodness of the results of all these equations is decided based on root mean square error (RMSE). Keywords: Gait Analysis; Biomechanics; C3D files; Anybody Software; Root mean square error (RMSE); Electromyography(EMG); Open Sim; Mokka Analysis; Any Body Analysis; MLS viewer; Mat Lab Modeling.