Functional Electrical Stimulation Induced Cadence Control of a Hand Cycle

Abstract: Functional electrical stimulation (FES) has become a popular and successful form of rehabilitation for people with neurological conditions such spinal cord injury or stroke. FES is the direct application of electrical current across the motor neurons of a muscle to generate artificial muscle contractions to perform functional tasks. Arm-cycling is a beneficial rehabilitation activity and motivation exists to use FES in arm-cycling. It has previously been shown that closed-loop FES control can be designed to achieve accurate, repetitive motion. In a previous study, a robust sliding-mode controller was used to track a desired crank cycle cadence (crank velocity) on a decoupled hand cycle. For this thesis the hand-cycle was modified to yield an improved tracking performance. Using a combination of FES and volition, experimental results from three able-bodied participants are presented for the developed control system. Two protocols were ran, one of which activated the motor for all time and demonstrated an average cadence tracking error of -0.04 ± 2.83 revolutions per minute (RPM) for a desired cadence of 40 RPM. The second protocol deactivated the motor when the bicep was stimulated and demonstrated an average cadence tracking error of -0.02 ± 5.35 RPM.

A video showing an example experiment for the protocol where the motor was activated for all time is located below.

Full Thesis Found Here.

Note: This was my undergraduate honors thesis written with the aid of Christian Cousin, Brendon Allen, and Dr. Warren E. Dixon.