Augmented feedback for lower-limb amputees - Gait perturbation by vibrotactile stimulation of the patellar tendon : proof of concept

Details

Supervisors

Ronsse, Renaud ; Jankovski, Aleksandar

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical

Abstract

To contribute to research on augmented feedback for lower-limb amputees, I developped a gait perturbation experiment using inertial measurement units (IMUs) to obtain gait information in real time and activate a vibrotactile unit stimulating the patellar tendon. This thesis is a proof of concept of the use of IMU signals to activate a vibrotactile stimulation at a given time of the gait (heel-strike +/- a delay). The shank angular velocity signal provided by the IMU is filtered and learned by adaptative oscillators to provide sufficiently strong detection conditions of foot-ground contact and the software and hardware delays are computed to be taken into account in the vibration activation. After a first experiment, the detection and activation conditions are re-examined and modified to overcome their weaknesses. The final real-time analysis of the signal comprises a 3Hz low-pass filter, a maxima detection based on 3 conditions and a step duration computation based on minima detection. The total delay between the real contact and the vibration of the unit is quantified and taken into account in the activation of the vibration.