Silvereye, sistema electrónico para el análisis de la marcha humana en el plano sagital a partir de sensores inerciales

Abstract

This work proposes an electronic system, Silvereye, focused on the analysis of human gait kinematics based on inertial sensors. This system is a tool to perform clinical diagnoses and monitor rehabilitation processes, since it is compact, portable and wireless, allowing gait processes to be measured non-invasively and without altering them. In addition to exposing the physical and logical topologies of the system, this work proposes an algorithmic procedure to align the axes of an inertial sensor with those of a corresponding lower segment, so that the sensor can be arbitrarily located in the segment. Additionally, the system implements a method to calculate the joint angles of flexion / extension (equivalent to the movements of the lower segments in the sagittal plane) and provides an interface that allows the movements of the user to be represented online using a three-dimensional avatar. The system was tested on an ideal joint and on a human knee using a two-dimensional vision system as a means of comparison. When comparing the calculated sagittal angles and the references obtained from the vision system, a mean square error (standard deviation) of 1.65 ° (0.55 °) is obtained for tests on an ideal joint and 1.84 ° (0.48 °) for tests on a human knee, with a correlation of r = 0.99 in both cases.