Dynamic simulation of a human gait and design problems of the lower limb prostheses

Paper in proceeding, 1999

In this paper the methodology and the numerical algorithm are proposed such as suitable both for the dynamic simulation of a human gait and for solving of the design problems of the lower limb prostheses. The methodology is based on the combination of the optimal control theory and the mathematical modeling with broad utilization of the data obtained from the biomechanical experiments. A special procedure is used for converting the initial optimal control problems for the highly nonlinear and complex bipedal locomotion system into the standard nonlinear programming problems. It is made by approximation of the independent variable functions using the combination of a spline and the Fourier series and the solution of the semi-inverse dynamics problem. The key feature of the algorithm proposed is its high numerical effectiveness and the possibility to satisfy many restrictions imposed on the phase coordinates of the system automatically and accurately. The proposed methodology is illustrated by the computer simulation of a human gait and the numerical results of solution of the design problems of the energy-optimal above-knee prostheses with several types of the structure of the knee mechanisms.