Design and evaluation of a vibrotactile feedback system to improve volitional myoelectric control for robotic transtibial prostheses: A preliminary study

In this paper, we propose a vibrotactile stimulation system and explore the potential of combining it with volitional myoelectric control for robotic transtibial prostheses. The proposed system consists of six vibrators, three on the anterior side of the thigh and the other three on the posterior side. Six able-bodied subjects and two transtibial amputee subjects participated in the study, and three experiments were performed. The first two experiments were designed to evaluate subjects' ability to perceive vibrotactile stimulations and make fast response. In the third experiment, we aimed to investigate the necessity of adding vibrotactile feedback to the loop of volitional myoelectric control. Experimental results indicate that subjects are able to discriminate stimulations produced by different vibrators, and detect the change of stimulation positions with small time delay. Furthermore, the addition of vibrotactile feedback improves the performance of controlling a virtual ankle to reach target positions. These preliminary results validate the promise of applying the vibrotactile stimulation system for robotic transtibial prosthesis control.