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arXiv · 1309.7937

Stationary Cycling Induced by Switched Functional Electrical Stimulation Control

Matthew J. Bellman·Teng-Hu Cheng·Ryan J. Downey·Warren E. Dixon
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Abstract

Functional electrical stimulation (FES) is used to activate the dysfunctional lower limb muscles of individuals with neuromuscular disorders to produce cycling as a means of exercise and rehabilitation. However, FES-cycling is still metabolically inefficient and yields low power output at the cycle crank compared to able-bodied cycling. Previous literature suggests that these problems are symptomatic of poor muscle control and non-physiological muscle fiber recruitment. The latter is a known problem with FES in general, and the former motivates investigation of better control methods for FES-cycling.In this paper, a stimulation pattern for quadriceps femoris-only FES-cycling is derived based on the effectiveness of knee joint torque in producing forward pedaling. In addition, a switched sliding-mode controller is designed for the uncertain, nonlinear cycle-rider system with autonomous state-dependent switching. The switched controller yields ultimately bounded tracking of a desired trajectory in the presence of an unknown, time-varying, bounded disturbance, provided a reverse dwell-time condition is satisfied by appropriate choice of the control gains and a sufficient desired cadence. Stability is derived through Lyapunov methods for switched systems, and experimental results demonstrate the performance of the switched control system under typical cycling conditions.

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Matthew J. Bellman, Teng-Hu Cheng, Ryan J. Downey, Warren E. Dixon. 2013-09-30. Stationary Cycling Induced by Switched Functional Electrical Stimulation Control. https://arxiv.org/abs/1309.7937

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