A Wearable Ultrasound System for Sensing Muscular Morphological Deformations

Noninvasive monitoring of muscle contraction, which provides information about muscle morphological deformations, has a great potential in medical applications, such as stroke rehabilitation and prosthesis control. This paper presents a wearable multichannel A-mode ultrasound system for the multiperspective muscle contraction detection against its existing bulky ultrasound sensing counterpart. The system consists of a waveform generator and a waveform amplifier for ultrasound excitation, as well as a signal processing module for echo receiving, amplifying, and transmitting. In addition, a miniaturized transducer was optimized for muscle contraction monitoring using 1-3 piezoelectric composite. The system's superiorities on excitation pulse, detection depth, and axial resolution were validated by the evaluation experiments. And in vivo muscle deformation detection and virtual prosthesis control experiments (target achievement control test) demonstrated its ability in rehabilitation applications, with a task completion rate of 100% and path efficiency of 93.30%. These results confirmed the reliability of the proposed ultrasound system and paved the way for its applications in rehabilitation treatment and prosthesis research.