Switched Control of Cadence During Stationary Cycling Induced by Functional Electrical Stimulation

• Published in: IEEE transactions on neural systems and rehabilitation engineering 2016-12, Vol.24 (12), p.1373-1383
• Main Authors: Bellman, Matthew J., Cheng, Teng-Hu, Downey, Ryan J., Hass, Chris J., Dixon, Warren E.
• Format: Article
• Language: English
• Subjects: Adult; Bicycling; Computer Simulation; Control systems; Electric Stimulation Therapy - methods; Electrical stimulation; Electrical stimuli; Feasibility studies; Functional electrical stimulation (FES); Hip; Hip Joint - physiopathology; Humans; Knee; Knee Joint - physiopathology; Lyapunov methods; Male; medical control systems; Models, Biological; Movement disorders; Movement Disorders - physiopathology; Movement Disorders - rehabilitation; Muscle Contraction; Muscle, Skeletal - physiopathology; Muscles; Neurodegenerative diseases; Neurological diseases; Neuromuscular stimulation; Parkinson's disease; Physical Exertion; Rehabilitation; switched control; Switched systems; Therapy, Computer-Assisted - methods; Torque
• ISSN: 1534-4320; 1558-0210
• DOI: 10.1109/TNSRE.2015.2500180

Functional electrical stimulation (FES) can be used to activate the dysfunctional lower limb muscles of individuals with neurological disorders to produce cycling as a means of rehabilitation. However, previous literature suggests that poor muscle control and nonphysiological muscle fiber recruitment during FES-cycling causes lower efficiency and power output at the cycle crank than able-bodied cycling, thus motivating the investigation of improved control methods for FES-cycling. In this paper, a stimulation pattern is designed based on the kinematic effectiveness of the rider's hip and knee joints to produce a forward torque about the cycle crank. A robust controller is designed for the uncertain, nonlinear cycle-rider system with autonomous, state-dependent switching. Provided sufficient conditions are satisfied, the switched controller yields ultimately bounded tracking of a desired cadence. Experimental results on four able-bodied subjects demonstrate cadence tracking errors of 0.05 ±1.59 and 5.27 ±2.14 revolutions per minute during volitional and FES-induced cycling, respectively. To establish feasibility of FES-assisted cycling in subjects with Parkinson's disease, experimental results with one subject demonstrate tracking errors of 0.43 ±4.06 and 0.17 ±3.11 revolutions per minute during volitional and FES-induced cycling, respectively.