A Multiplexed Sonomyography System for Proprioceptive Proportional Control of Biomechatronic Interfaces

Sonomyography is an ultrasound-imaging-based technique that measures muscle activity. Real-time imaging of deep-seated muscle activity enables robust and intuitive biomechatronic control. However, the form factor of clinical ultrasound systems limits the practical utility of sonomyography. Therefore, recent investigations aim towards developing wearable ultrasound systems to utilize sonomyography for biomechatronic interfacing. In this paper, a wearable, multiplexed sonomyography transducer array for real-time sensing muscle activity has been presented. The forearm-muscle activity was quantified using a computationally inexpensive, correlation-based metric to generate a sonomyography signal. The sonomyography signal was then used to perform a human-computer interaction-based target achievement task involving one degree of freedom control in real-time. Results show that participants achieved the targets with an average success rate of > 96 % for a target width of 10%, with minimal training. The results demonstrate the potential of a multiplexed sonomyography system for intuitive control of biomechatronic interfaces.