Parametric modeling of kinetic-kinematic polycentric mechanical knee

Abstract

The transfemoral amputation involves the loss of the knee joint, which is recognized as a common and complex case. The knee is replaced by a polycentric mechanism, which is exposed to high levels of structural stress. Therefore, mathematical models of the mechanics knees are commonly used to kinetic analysis and simulation and determine possible failures. This paper describes the procedure for determining a kinematic model of a four-bars polycentric knee using a geometric analysis and the Grashof Law for a double rocker. The kinetic model was found using parametric, linear and nonlinear identification techniques, for this were used knee force and angle data supplied by the free database Orthoload. The model couples the kinetics and kinematics ARX structure, these can represent bending angles 110 ° and the total force exerted on the instantaneous center of rotation of the knee.