A surface neuromuscular electrical stimulation device for universal cartesian force control in humans

Abstract

In recent years, neuromuscular electrical stim-ulation (NMES) has found many applications both within the medical field and outside. While this technology has been widely recognized as a valid tool for rehabilitative and assistive applications, most solutions presented in the literature seem to focus on highly specific cases and facili-tate very selective movements. In this article, we present a novel surface stimulation- based prototype which, cou-pled with an internally designed musculoskeletal model, allows to induce the output of generalized forces at the human end- effector in Cartesian coordinates. The control has been validated here through a 6- axis force- torque sen-sor coupled with a robotic manipulator. Thus, the meas-ured forces at the user's end- effector were compared to the commanded forces. The results confirm that open- loop control of the output force is possible with an average cor-relation coefficient between commanded and measured force output direction >0.7. This could eventually provide full, general- purpose impedance control of the human neuromuscular system, which would allow to induce ar-bitrary movements in the peri- personal space.