Research: Bionics
Closed-Loop Electrical Stimulation

Electrical stimulation is an often prescribed clinical treatment to obtain physiological and functional benefits for impaired individuals. Often, electrical stimulation is applied to aid the recovery of the size and strength of skeletal muscle. For these tasks, open-loop pulse trains are often sufficient to exercise the muscle. Another goal for electrical stimulation is to recover muscle function through plastic changes in the neuromuscular system by eliciting accurate, precise, and repetitive movements that result in standing, stepping, reaching, etc. (i.e., functional electrical stimulation (FES)). Specifically, clinical evidence shows that sensory afferent feedback provided by FES coupled with repetitive task-related muscle activation can facilitate cortical reorganization. Therefore, coordinated motion of multiple muscle groups/limbs over long durations is motivated to yield rehabilitative outcomes; yet, numerous challenges persist to yield effective coordination of the limbs. Some of these challenges include: the inherent unknown and variable delay of muscle response to stimulation (i.e., input delay), the muscle response to stimulation is nonlinear and uncertain, for coordinated motions the control input has to switch between multiple muscle groups, external stimulation of muscle leads to rapid fatigue.

FES Cycling

FES-induced cycling is a common rehabilitation treatment for individuals with upper motor neuron lesions, and numerous physiological and psychological benefits have since been demonstrated. Current clinical cycles used fixed stimulation patterns and incorporate a motor which maintains a desired cycle cadence. The focus of this research is to develop closed-loop control methods to address existing performance gaps in commercial FES cycles. On-going research efforts focus on open questions related to amalgamation of man and machine in terms of when to use a motor to control cycling cadence/power and when to induce cycling through a person's muscles.

Upper Extremity Exoskeleton

A person's limb can be controlled to follow a desired (force/position) trajectory through either a motorized exoskeleton or induced through muscle stimulation. Questions in this project are related to the balance between these different means to follow a trajectory for prolonged exercise.


Ongoing Projects
NSF: Switched Adaptive Control Methods for Electrical Stimulation Induced Cycling

Completed Projects
NSF CAREER: Nonlinear Control of Human Skeletal Muscle
NSF: Mitigation of Fatigue Induced Effects in Skeletal Muscle Through Closed-Loop Neuromuscular Electrical Stimulation
FL DOH: An External Device for Rehabilitation of Airway Protective Behaviors

Related NCR Bionics Publications