Real-Time Embedded System for Event-Driven sEMG Acquisition and Functional Electrical Stimulation Control

The analysis of the surface ElectroMyoGraphic (sEMG) signal for controlling the Functional Electrical Stimulation (FES) therapy is being widely accepted in the active rehabilitation field due to the high benefits in the restoration of functional movements for subjects affected by neuro-muscular disorders. Portability and real-time functionalities are major concerns, and, among the others, two correlated challenges are the development of an embedded system and the implementation of lightweight signal processing approaches. In this respect, the event-driven nature of the Average Threshold Crossing (ATC) approach, considering its high correlation with the muscle force and the sparsity of its representation, could be an optimal solution. In this paper we present an embedded ATC-FES control system equipped with a multi-platform software featuring an easy-to-use Graphical User Interface (GUI). The system has been tested on 5 healthy subjects in order to test its effectiveness: we obtained a correlation coefficient value of 0.86±0.07, as similarity index between the healthy movement and the stimulated one during the elbow flexion exercise.