Telerehabilitation Through a Remotely Operated Motorized Functional Electric Stimulation Actuated Cycle

Neuromuscular disorders (NDs) affect millions of people each year, many of whom are prescribed functional electrical stimulation (FES) rehabilitative cycling. However, it is often difficult for many with NDs to attend regularly scheduled physical therapy sessions, a fact which is exasperated by the ongoing COVID-19 pandemic. This article details the development of a teleoperated FES-actuated rehabilitation system for two use cases: a remote physical therapy session for people not able to attend in person, and a rehab-by-wire style system where the rehabilitation participant sets the desired trajectory of the FES-actuated lower-body cycle using a motorized hand-cycle, thus coordinating the upper and lower limbs. In both cases, the lower-body rehabilitation cycle has a split-crank to capture asymmetries in lower-body performance. Lyapunov-based analysis methods are used to prove global exponential tracking to the desired position and cadence determined by the master-cycle system. Five people were tested for each use case, where the teleoperated FES-actuated rehabilitative lower-body cycling system resulted in an average rms position error (calculated across both use cases) of 6.14° and an average rms cadence error of 3.77 RPM, despite an unpredictable, variable desired cadence. The calculated average position error was found to be 0.04°+/−5.96°, thus eliminating undesirable steady-state position errors reported in prior works.