Wearable system for elbow angles estimation based on a polymer encapsulated conductive textile

Wearable devices are finding their use from activities of daily living to clinical evaluations for monitoring different physiological parameters. Among others, estimation and tracking of limb movements are crucial especially in rehabilitation medicine and in supporting the worker's health. The purpose of this works is to develop and test a wearable system based on an encapsulated conductive sensor, able to track the elbow joint flexion-extension movements, to count the number of movement repetitions, and to estimate the elbow joint angles during the movement. The feasibility assessment of the proposed system has been carried out on 2 healthy volunteers mimicking a rehabilitation task and occupation setting one. A motion capture system has been used as reference system for the elbow movements. Results showed a good agreement between the data collected by the wearable system and the ones provided by the reference one. Indeed, the output of the two systems during the trials was similar, highlighting the capability of the wearable to follow the elbow flexion-extensions. In addition, the two systems tracked the same number of flexion-extensions. Finally, promising results were also obtained in the most challenging task, which is the estimation of the elbow angle. Indeed, the agreement, calculated in terms of mean absolute error, has been always lower than 7.5°.