title: Predictor-based compensation for electromechanical delay during neuromuscular electrical stimulation.
abstract: Electromechanical delay (EMD) is a biological artifact that arises due to a time lag between electrical excitation and tension development in a muscle. EMD is known to cause degraded performance and instability during neuromuscular electrical stimulation (NMES). Compensating for such input delay is complicated by the unknown nonlinear muscle force-length and muscle force-velocity relationships. This paper provides control development and a mathematical stability analysis of a NMES controller with a predictive term that actively accounts for EMD. The results are obtained through the development of a novel predictor-type method to address the delay in the voltage input to the muscle. Lyapunov-Krasovskii functionals are used within a Lyapunov-based stability analysis to prove semi-global uniformly ultimately bounded tracking. Experiments on able-bodied volunteers illustrate the performance and robustness of the developed controller during a leg extension trajectory following task.
authors.affiliation: Department of Physiology, University of Alberta, Edmonton, Canada. nitin2@ualberta.ca
authors.forename: Nitin
authors.initials: N
authors.lastname: Sharma
authors.forename: Chris M
authors.initials: CM
authors.lastname: Gregory
authors.forename: Warren E
authors.initials: WE
authors.lastname: Dixon
mesh_terms: D000328:Adult; D000465:Algorithms; D004558:Electric Stimulation / Q000295:instrumentation* / Q000379:methods; D004576:Electromyography; D004594:Electrophysiology; D004867:Equipment Design; D005260:Female; D005544:Forecasting; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D055595:Mechanical Phenomena; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D017711:Nonlinear Dynamics; D055815:Young Adult