Modeling and simulation of prosthetic gait using a 3D model based on perturbation functions

Abstract

The work describes the method of construction of a lower limb prosthesis, both below and above the knee. It describes the computer-aided design basis and the digital patient model with which the prosthesis is designed and tested in a fully virtual environment. The virtual patient model is the basis of the entire system, using a biomechanical model that takes into account patient characteristics such as anthropometric indicators. The program uses automated and knowledge-based approaches in order to replace the current development process, mainly manual, with a virtual one. A set of tools is used to design, configure and test the prosthesis. Prosthetic modeling allows configuring and generating a threedimensional model of the prosthesis. The virtual test environment allows the prosthesis to virtually configure the artificial leg and simulate the patient's posture and movements, checking functionality and configuration. A gait model has been developed. For this purpose, the analogy of the double pendulum with the flesh segment of the lower limb was used, which allows to evaluate the gait model as a system using simple final figures or connections. The system representing association of segments is used, the energy exchange between links of the system is analyzed using the Lagrange method. The association analysis is developed by calculating inverse kinematics, which determines the trajectory and position of the system in order to find the forces that carry out this movement and energy transfer. Taken as a double pendulum, the lower limb has mass and length values based on the weight and height of each part. The obtained values were derived from anthropometric data of the subject.